Publications (83)
Testing Gravity with Binary Pulsars in the SKA Era
V. Venkatraman Krishnan, L. Shao, V. Balakrishnan +21
Binary (and trinary) radio pulsars are natural laboratories in space for understanding gravity in the strong field regime, with many unique and precise tests carried out so far, in…
MeerKAT discovery of 13 new pulsars in Omega Centauri
W. Chen, P. C. C. Freire, A. Ridolfi +21
The most massive globular cluster in our Galaxy, Omega Centauri, is an interesting target for pulsar searches, because of its multiple stellar populations and the intriguing possib…
LOFT: the Large Observatory For X-ray Timing
M. Feroci, J. W. den Herder, E. Bozzo +245
The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is curren…
Constraints on the flux of Ultra-High Energy neutrinos from WSRT observations
S. Buitink, O. Scholten, J. Bacelar +7
Ultra-high energy (UHE) neutrinos and cosmic rays initiate particle cascades underneath the Moon's surface. These cascades have a negative charge excess and radiate Cherenkov radio…
Constraining Pulsar Emission Physics through Radio/Gamma-Ray Correlation of Crab Giant Pulses
A. V. Bilous, V. I. Kondratiev, M. A. McLaughlin +6
To constrain the giant pulse (GP) emission mechanism and test the model of Lyutikov (2007) of GP emission, we are carrying out a campaign of simultaneous observations of the Crab p…
LOFAR observations of PSR B0943+10: profile evolution and discovery of a systematically changing profile delay in Bright mode
A. Bilous, J. Hessels, V. Kondratiev +10
We present broadband, low-frequency (25-80 MHz and 110-190 MHz) LOFAR observations of PSR B0943+10, with the goal of better illuminating the nature of its enigmatic mode-switching…
A 6.5-GHz Multibeam Pulsar Survey
S. D. Bates, S. Johnston, D. R. Lorimer +10
A survey of the Galactic plane in the region , was carried out using the seven-beam Parkes Methanol Multibeam (MMB) receive…
A very brief description of LOFAR - the Low Frequency Array
H. Falcke, M. P. van Haarlem, A. G. de Bruyn +28
LOFAR (Low Frequency Array) is an innovative radio telescope optimized for the frequency range 30-240 MHz. The telescope is realized as a phased aperture array without any moving p…
Statistical properties of giant pulses from the Crab pulsar
M. V. Popov, B. Stappers
We have studied the statistics of giant pulses from the Crab pulsar for the first time with particular reference to their widths. We have analyzed data collected during 3.5 hours o…
RFI Flagging Implications for Short-Duration Transients
Y. Cendes, P. Prasad, A. Rowlinson +24
With their wide fields of view and often relatively long coverage of any position in the sky in imaging survey mode, modern radio telescopes provide a data stream that is naturally…
A LOFAR census of non-recycled pulsars: average profiles, dispersion measures, flux densities, and spectra
A. Bilous, V. Kondratiev, M. Kramer +24
We present first results from a LOFAR census of non-recycled pulsars. The census includes almost all such pulsars known (194 sources) at declinations and Galac…
Testing Gravity with Binary Pulsars in the SKA Era
V. Venkatraman Krishnan, L. Shao, V. Balakrishnan +21
Binary (and trinary) radio pulsars are natural laboratories in space for understanding gravity in the strong field regime, with many unique and precise tests carried out so far, in…
Radio emission evolution, polarimetry and multifrequency single pulse analysis of the radio magnetar PSR J1622-4950
L. Levin, M. Bailes, S. D. Bates +11
Here we report on observations of the radio magnetar PSR J1622-4950 at frequencies from 1.4 to 17 GHz. We show that although its flux density is varying up to a factor of ~10 withi…
The High Time Resolution Universe Survey VI: An Artificial Neural Network and Timing of 75 Pulsars
S. D. Bates, M. Bailes, B. R. Barsdell +19
We present 75 pulsars discovered in the mid-latitude portion of the High Time Resolution Universe survey, 54 of which have full timing solutions. All the pulsars have spin periods…
A Population of Fast Radio Bursts at Cosmological Distances
D. Thornton, B. Stappers, M. Bailes +17
Searches for transient astrophysical sources often reveal unexpected classes of objects that are useful physical laboratories. In a recent survey for pulsars and fast transients we…
The geometry of PSR B0031-07
R. Smits, D. Mitra, B. Stappers +4
Here we present the results from an analysis of a multifrequency simultaneous observation of PSR B003107. We have constructed a geometrical model, based on an empirical relation…
Fast Radio Bursts in the Era of the Vera C. Rubin Observatory's Legacy Survey of Space and Time
C. W. James, B. Smith, K. Dage +12
Identifying the host galaxies of fast radio bursts (FRBs), and comparing their redshifts and dispersion measures, has unlocked a new probe of the cosmological distribution of ionis…
The LOFAR radio environment
A. R. Offringa, A. G. de Bruyn, S. Zaroubi +93
Aims: This paper discusses the spectral occupancy for performing radio astronomy with the Low-Frequency Array (LOFAR), with a focus on imaging observations. Methods: We have analys…
The Large Observatory For x-ray Timing
M. Feroci, J. W. den Herder, E. Bozzo +341
The Large Observatory For x-ray Timing (LOFT) was studied within ESA M3 Cosmic Vision framework and participated in the final down-selection for a launch slot in 2022-2024. Thanks…
Searches for gravitational waves from known pulsars with S5 LIGO data
The LIGO Scientific Collaboration, The Virgo Collaboration, B. P. Abbott +678
We present a search for gravitational waves from 116 known millisecond and young pulsars using data from the fifth science run of the LIGO detectors. For this search ephemerides ov…
The Commensal Real-time ASKAP Fast Transients (CRAFT) survey
Jean-Pierre Macquart, the CRAFT collaboration, : +37
We are developing a purely commensal survey experiment for fast (<5s) transient radio sources. Short-timescale transients are associated with the most energetic and brightest singl…
Chandra and RXTE studies of the X-ray/gamma-ray millisecond pulsar PSR J0218+4232
L. Kuiper, W. Hermsen, B. Stappers
We report on high-resolution spatial and timing observations of the millisecond pulsar PSR J0218+4232 performed with the Chandra X-ray Observatory (CXO) and the Rossi X-ray Timing…
A polarized fast radio burst at low Galactic latitude
E. Petroff, S. Burke-Spolaor, E. F. Keane +35
We report on the discovery of a new fast radio burst, FRB 150215, with the Parkes radio telescope on 2015 February 15. The burst was detected in real time with a dispersion measure…
The NuMoon experiment: first results
S. Buitink, J. Bacelar, R. Braun +7
The NuMoon project uses the Westerbork Synthesis Radio Telescope to search for short radio pulses from the Moon. These pulses are created when an ultra high energy cosmic ray or ne…
A parallax distance and mass estimate for the transitional millisecond pulsar system J1023+0038
A. T. Deller, A. M. Archibald, W. F. Brisken +9
The recently discovered transitional millisecond pulsar system J1023+0038 exposes a crucial evolutionary phase of recycled neutron stars for multiwavelength study. The system, comp…
Enhanced Optical Emission During Crab Giant Radio Pulses
A. Shearer, B. Stappers, P. O' Connor +3
We detected a correlation between optical and giant radio pulse emission from the Crab pulsar. Optical pulses coincident with the giant radio pulses were on average 3% brighter tha…
A new limit on the Ultra-High-Energy Cosmic-Ray flux with the Westerbork Synthesis Radio Telescope
S. ter Veen, S. Buitink, H. Falcke +6
A particle cascade (shower) in a dielectric, for example as initiated by an ultra-high energy cosmic ray, will have an excess of electrons which will emit coherent Äerenkov radiat…
The international pulsar timing array project: using pulsars as a gravitational wave detector
G. Hobbs, A. Archibald, Z. Arzoumanian +55
The International Pulsar Timing Array project combines observations of pulsars from both Northern and Southern hemisphere observatories with the main aim of detecting ultra-low fre…
The High Time Resolution Universe Pulsar Survey VIII: The Galactic millisecond pulsar population
L. Levin, M. Bailes, B. R. Barsdell +17
We have used millisecond pulsars (MSPs) from the southern High Time Resolution Universe (HTRU) intermediate latitude survey area to simulate the distribution and total population o…
Studying the solar system with the International Pulsar Timing Array
R. N. Caballero, Y. J. Guo, K. J. Lee +77
Pulsar-timing analyses are sensitive to errors in the solar-system ephemerides (SSEs) that timing models utilise to estimate the location of the solar-system barycentre, the quasi-…
Optimal Radio Window for the Detection of Ultra-High-Energy Cosmic Rays and Neutrinos off the Moon
O. Scholten, J. Bacelar, R. Braun +4
When high-energy cosmic rays impinge on a dense dielectric medium, radio waves are produced through the Askaryan effect. We show that at wavelengths comparable to the length of the…
A MeerKAT Survey of Nearby Novalike Cataclysmic Variables
D. M. Hewitt, M. L. Pretorius, P. A. Woudt +17
We present the results of MeerKAT radio observations of eleven nearby novalike cataclysmic variables. We have detected radio emission from IM Eri, RW Sex, V3885 Sgr and V603 Aql. W…
Fifteen new millisecond pulsars in 47 Tucanae
W. Chen, D. Risbud, P. C. C. Freire +16
47 Tucanae is one of the largest, brightest, and closest globular clusters to Earth. It hosts an exotic stellar population with stellar dynamics that indicate a complex evolution h…
M87 at metre wavelengths: the LOFAR picture
F. de Gasperin, E. Orru', M. Murgia +92
M87 is a giant elliptical galaxy located in the centre of the Virgo cluster, which harbours a supermassive black hole of mass 6.4x10^9 M_sun, whose activity is responsible for the…
Understanding the Neutron Star Population with the SKAO Telescopes
L. Levin, M. Bagchi, M. Burgay +12
The known population of non-accreting neutron stars is ever growing and currently consists of more than 3500 sources. Pulsar surveys with the SKAO telescopes will greatly increase…
LOFAR Observations of Swift J1644+57 and Implications for Short-Duration Transients
Y. Cendes, R. A. M. J. Wijers, J. D. Swinbank +25
Aims: We have analyzed low frequency radio data of tidal disruption event (TDE) Swift J1644+57 to search for a counterpart. We consider how brief transient signals (on the order of…
Improved flux limits for neutrinos with energies above 10 eV from observations with the Westerbork Synthesis Radio Telescope
O. Scholten, S. Buitink, J. Bacelar +7
Particle cascades initiated by ultra-high energy (UHE) neutrinos in the lunar regolith will emit an electromagnetic pulse with a time duration of the order of nano seconds through…
The High Time Resolution Universe Survey - III. Single-pulse searches and preliminary analysis
S. Burke-Spolaor, M. Bailes, S. Johnston +12
We present the search methods and initial results for transient radio signals in the High Time Resolution Universe (HTRU) Survey. The HTRU survey's single-pulse search, the softwar…
The SUrvey for Pulsars and Extragalactic Radio Bursts III: Polarization properties of FRBs 160102 & 151230
M. Caleb, E. F. Keane, W. van Straten +16
We report on the polarization properties of two fast radio bursts (FRBs): 151230 and 160102 discovered in the SUrvey for Pulsars and Extragalactic Radio Bursts (SUPERB) at the Park…
Searches for Gravitational Waves from Known Pulsars at Two Harmonics in 2015-2017 LIGO Data
The LIGO Scientific Collaboration, the Virgo Collaboration, B. P. Abbott +1149
We present a search for gravitational waves from 221 pulsars with rotation frequencies Hz. We use advanced LIGO data from its first and second observing runs spanning…
A real-time fast radio burst: polarization detection and multiwavelength follow-up
E. Petroff, M. Bailes, E. D. Barr +32
Fast radio bursts (FRBs) are one of the most tantalizing mysteries of the radio sky; their progenitors and origins remain unknown and until now no rapid multiwavelength follow-up o…
Status report of the NuMoon experiment
O. Scholten, S. Buitink, J. Bacelar +7
We show that at wavelengths comparable to the length of the shower produced by an Ultra-High Energy cosmic ray or neutrino, radio signals are an extremely efficient way to detect t…
Prospects for accurate distance measurements of pulsars with the SKA: enabling fundamental physics
R. Smits, S. J. Tingay, N. Wex +2
Parallax measurements of pulsars allow for accurate measurements of the interstellar electron density and contribute to accurate tests of general relativity using binary systems. T…
The LOFAR Known Pulsar Data Pipeline
A. Alexov, J. W. T. Hessels, J. D. Mol +2
Transient radio phenomena and pulsars are one of six LOFAR Key Science Projects (KSPs). As part of the Transients KSP, the Pulsar Working Group (PWG) has been developing the LOFAR…
Understanding the Neutron Star Population with the SKAO telescopes
L. Levin, M. Bagchi, M. Burgay +13
The known population of non-accreting neutron stars is ever growing and currently consists of more than 3500 sources. Pulsar surveys with the SKAO telescopes will greatly increase…
The High Time Resolution Universe Pulsar Survey -- XVIII. The reprocessing of the HTRU-S Low Lat survey around the Galactic centre using a Fast Folding Algorithm pipeline for accelerated pulsars
J. Wongphechauxsorn, D. J. Champion, M. Bailes +18
The HTRU-S Low Latitude survey data within 1of the Galactic Centre (GC) were searched for pulsars using the Fast Folding Algorithm (FFA). Unlike traditional Fast Fourier…
X-rays from the mode-switching PSR B0943+10
S. Mereghetti, L. Kuiper, A. Tiengo +15
New simultaneous X-ray and radio observations of the archetypal mode-switching pulsar PSR B0943+10 have been carried out with XMM-Newton and the LOFAR, LWA and Arecibo radio telesc…
A coherent radio burst from an X-ray neutron star in the Carina Nebula
K. M. Rajwade, J. Tian, G. Younes +10
The neutron star zoo comprises several sub-populations that range from energetic magnetars and thermally emitting X-ray neutron stars to radio-emitting pulsars. Despite studies ove…
The semicentennial binary system PSR J2032+4127 at periastron: X-ray photometry, optical spectroscopy and SPH modelling
M. J. Coe, A. T. Okazaki, I. A. Steele +7
X-ray photometry and optical spectra are presented covering the periastron passage of the highly-eccentric, ~50 year binary system PSR J2032+4127 in November 2017. This system cons…
From Spin Noise to Systematics: Stochastic Processes in the First International Pulsar Timing Array Data Release
L. Lentati, R. M. Shannon, W. A. Coles +80
We analyse the stochastic properties of the 49 pulsars that comprise the first International Pulsar Timing Array (IPTA) data release. We use Bayesian methodology, performing model…
PSR J2222--0137. I. Improved physical parameters for the system
Y. J. Guo, P. C. C. Freire, L. Guillemot +14
The PSR J2222-0137 binary system is a unique laboratory for testing gravity theories. To fully exploit its potential for the tests, we aim to improve the measurements of its physic…
The TRAPUM L-band survey for pulsars in Fermi-LAT gamma-ray sources
C. J. Clark, R. P. Breton, E. D. Barr +35
More than 100 millisecond pulsars (MSPs) have been discovered in radio observations of gamma-ray sources detected by the Fermi Large Area Telescope (LAT), but hundreds of pulsar-li…
Pulsar Wind Nebulae in the SKA era
J. D. Gelfand, R. P. Breton, C. -Y. Ng +4
Neutron stars lose the bulk of their rotational energy in the form of a pulsar wind: an ultra-relativistic outflow of predominantly electrons and positrons. This pulsar wind signif…
Constraining the era of helium reionization using fast radio bursts
M. Caleb, C. Flynn, B. Stappers
The discovery of fast radio bursts (FRBs) about a decade ago opened up new possibilities for probing the ionization history of the Intergalactic Medium (IGM). In this paper we stud…
Searching for continuous Gravitational Waves in the second data release of the International Pulsar Timing Array
M. Falxa, S. Babak, P. T. Baker +123
The International Pulsar Timing Array 2nd data release is the combination of datasets from worldwide collaborations. In this study, we search for continuous waves: gravitational wa…
The High Time Resolution Universe Survey II: Discovery of 5 Millisecond Pulsars
S. D. Bates, M. Bailes, N. D. R. Bhat +13
We present the discovery of 5 millisecond pulsars found in the mid-Galactic latitude portion of the High Time Resolution Universe (HTRU) Survey. The pulsars have rotational periods…
MeerKAT caught a Mini Mouse: serendipitous detection of a young radio pulsar escaping its birth sit
S. E. Motta, J. D. Turner, B. Stappers +4
In MeerKAT observations pointed at a Galactic X-ray binary located on the Galactic plane we serendipitously discovered a radio nebula with cometary-like morphology. The feature, wh…
Are all fast radio bursts repeating sources?
M. Caleb, B. Stappers, K. Rajwade +1
We present Monte-Carlo simulations of a cosmological population of repeating fast radio burst (FRB) sources whose comoving density follows the cosmic star formation rate history. W…
Transformation of a Star into a Planet in a Millisecond Pulsar Binary
M. Bailes, S. D. Bates, V. Bhalerao +15
Millisecond pulsars are thought to be neutron stars that have been spun-up by accretion of matter from a binary companion. Although most are in binary systems, some 30% are solitar…
Understanding pulsar magnetospheres with the SKA
A. Karastergiou, S. Johnston, N. Andersson +14
The SKA will discover tens of thousands of pulsars and provide unprecedented data quality on these, as well as the currently known population, due to its unrivalled sensitivity. He…
The SUrvey for Pulsars and Extragalactic Radio Bursts II: New FRB discoveries and their follow-up
S. Bhandari, E. F. Keane, E. D. Barr +47
We report the discovery of four Fast Radio Bursts (FRBs) in the ongoing SUrvey for Pulsars and Extragalactic Radio Bursts (SUPERB) at the Parkes Radio Telescope: FRBs 150610, 15120…
Initial deep LOFAR observations of Epoch of Reionization windows: I. The North Celestial Pole
S. Yatawatta, A. G. de Bruyn, M. A. Brentjens +86
The aim of the LOFAR Epoch of Reionization (EoR) project is to detect the spectral fluctuations of the redshifted HI 21cm signal. This signal is weaker by several orders of magnitu…
Optimized Trigger for Ultra-High-Energy Cosmic-Ray and Neutrino Observations with the Low Frequency Radio Array
K. Singh, M. Mevius, O. Scholten +100
When an ultra-high energy neutrino or cosmic ray strikes the Lunar surface a radio-frequency pulse is emitted. We plan to use the LOFAR radio telescope to detect these pulses. In t…
The High Time Resolution Universe Pulsar Survey -- XV: completion of the intermediate latitude survey with the discovery and timing of 25 further pulsars
M. Burgay, B. Stappers, M. Bailes +21
We report on the latest six pulsars discovered through our standard pipeline in the intermediate-latitude region (|b| < 15 deg) of the Parkes High Time Resolution Universe Survey (…
Narrow-band search for gravitational waves from known pulsars using the second LIGO observing run
The LIGO Scientific Collaboration, the Virgo Collaboration, B. P. Abbott +1135
Isolated spinning neutron stars, asymmetric with respect to their rotation axis, are expected to be sources of continuous gravitational waves. The most sensitive searches for these…
Detecting UHE Cosmics & Neutrinos off the Moon; an Optimal Radio Window
O. Scholten, J. Bacelar, R. Braun +4
We show that at wavelengths comparable to the length of the shower produced by an Ultra-High Energy cosmic ray or neutrino, radio signals are an extremely efficient way to detect t…
PSR J17552550: A young radio pulsar with a massive, compact companion
C. Ng, M. U. Kruckow, T. M. Tauris +9
Radio pulsars found in binary systems with short orbital periods are usually fast spinning as a consequence of recycling via mass transfer from their companion stars; this process…
Fast Transients at Cosmological Distances with the SKA
J. -P. Macquart, E. Keane, K. Grainge +14
Impulsive radio bursts that are detectable across cosmological distances constitute extremely powerful probes of the ionized Inter-Galactic Medium (IGM), intergalactic magnetic fie…
The High Time Resolution Universe Survey - V: Single-pulse energetics and modulation properties of 315 pulsars
S. Burke-Spolaor, S. Johnston, M. Bailes +11
We report on the pulse-to-pulse energy distributions and phase-resolved modulation properties for catalogued pulsars in the southern High Time Resolution Universe intermediate-lati…
High-Performance Computing for SKA Transient Search: Use of FPGA based Accelerators -- a brief review
R. Aafreen, R. Abhishek, B. Ajithkumar +34
This paper presents the High-Performance computing efforts with FPGA for the accelerated pulsar/transient search for the SKA. Case studies are presented from within SKA and pathfin…
Pulsar searches and timing with the SKA
R. Smits, M. Kramer, B. Stappers +3
The Square Kilometre Array (SKA) is a planned multi purpose radio telescope with a collecting area approaching 1 million square metres. One of the key science objectives of the SKA…
A high frequency search for radio pulsars in EGRET error boxes
M. J. Keith, S. Johnston, M. Kramer +3
We present a new survey for pulsars in the error boxes of the low-latitude EGRET sources 3EG J1027-5817, 3EG J1800-2338 and 3EG J1810-1032. Although all of these sources have been…
A deep campaign to characterize the synchronous radio/X-ray mode switching of PSR B0943+10
S. Mereghetti, L. Kuiper, A. Tiengo +14
We report on simultaneous X-ray and radio observations of the mode-switching pulsar PSR B0943+10 obtained with the XMM-Newton satellite and the LOFAR, LWA and Arecibo radio telesco…
Pulsar science with the Five hundred metre Aperture Spherical Telescope
R. Smits, D. R. Lorimer, M. Kramer +5
With a collecting area of 70 000 m^2, the Five hundred metre Aperture Spherical Telescope (FAST) will allow for great advances in pulsar astronomy. We have performed simulations to…
The MPIfR-MeerKAT Galactic Plane survey I -- System setup and early results
P. V. Padmanabh, E. D. Barr, S. S. Sridhar +30
Galactic plane radio surveys play a key role in improving our understanding of a wide range of astrophysical phenomena. Performing such a survey using the latest interferometric te…
Revival of the magnetar PSR J1622-4950: observations with MeerKAT, Parkes, XMM-Newton, Swift, Chandra, and NuSTAR
F. Camilo, P. Scholz, M. Serylak +205
New radio (MeerKAT and Parkes) and X-ray (XMM-Newton, Swift, Chandra, and NuSTAR) observations of PSR J1622-4950 indicate that the magnetar, in a quiescent state since at least ear…
The High Time Resolution Universe Pulsar Survey -- XVII. PSR J1325-6253, a low eccentricity double neutron star system from an ultra-stripped supernova
R. Sengar, V. Balakrishnan, S. Stevenson +20
The observable population of double neutron star (DNS) systems in the Milky Way allow us to understand the nature of supernovae and binary stellar evolution. Until now, all DNS sys…
A long-period radio transient active for three decades
N. Hurley-Walker, N. Rea, S. J. McSweeney +22
Recently several long-period radio transients have been discovered, with strongly polarised coherent radio pulses appearing on timescales between tens to thousands of seconds [1,2]…
The first multi-wavelength campaign of AXP 4U 0142+61 from radio to hard X-rays
P. R. den Hartog, L. Kuiper, W. Hermsen +5
For the first time a quasi-simultaneous multi-wavelength campaign has been performed on an Anomalous X-ray Pulsar from the radio to the hard X-ray band. 4U 0142+61 was an INTEGRAL…
ThunderKAT: The MeerKAT Large Survey Project for Image-Plane Radio Transients
R. Fender, P. A. Woudt, R. Armstrong +59
ThunderKAT is the image-plane transients programme for MeerKAT. The goal as outlined in 2010, and still today, is to find, identify and understand high-energy astrophysical process…
A strong magnetic field around the supermassive black hole at the centre of the Galaxy
R. P. Eatough, H. Falcke, R. Karuppusamy +20
The centre of our Milky Way harbours the closest candidate for a supermassive black hole. The source is thought to be powered by radiatively inefficient accretion of gas from its e…
Limits on anisotropy in the nanohertz stochastic gravitational-wave background
S. R. Taylor, C. M. F. Mingarelli, J. R. Gair +32
The paucity of observed supermassive black hole binaries (SMBHBs) may imply that the gravitational wave background (GWB) from this population is anisotropic, rendering existing ana…
Future mmVLBI Research with ALMA: A European vision
R. P. J. Tilanus, T. P. Krichbaum, J. A. Zensus +165
Very long baseline interferometry at millimetre/submillimetre wavelengths (mmVLBI) offers the highest achievable spatial resolution at any wavelength in astronomy. The anticipated…