Publications (24)
A Square Kilometre Array Pulsar Census
E. F. Keane, V. Graber, L. Levin +8
Most of the pulsar science case with the Square Kilometre Array (SKA) depends on long-term precision pulsar timing of a large number of pulsars, as well as astrometric measurements…
Apertif view of the OH Megamaser IRAS 10597+5926: OH 18 cm satellite lines in wide-area HI surveys
Kelley M. Hess, H. Roberts, H. Dénes +26
We present the serendipitous detection of the two main OH maser lines at 1667 and 1665 MHz associated with IRAS 10597+5926 at z = 0.19612 in the untargeted Apertif Wide-area Extrag…
Understanding pulsar magnetospheres with the SKAO
L. S. Oswald, A. Basu, M. Chakraborty +22
The SKA telescopes will bring unparalleled sensitivity across a broad radio band, a wide field of view across the Southern sky, and the capacity for sub-arraying, all of which make…
The best of both worlds: Combining LOFAR and Apertif to derive resolved radio spectral index images
R. Morganti, T. A. Oosterloo, M. Brienza +36
Supermassive black holes at the centres of galaxies can cycle through periods of activity and quiescence. Characterising the duty cycle of active galactic nuclei is crucial for und…
The low-frequency flattening of the radio spectrum of giant HII regions in M 101
L. GajoviÄ, V. Heesen, M. Brüggen +10
In galaxies, the flattening of the spectrum at low radio frequencies below 300 MHz has been the subject of some debate. A turnover at low frequencies could be caused by multiple ph…
LOFAR discovery and wide-band characterisation of an ultra-steep spectrum AGN radio remnant associated with Abell 1318
A. Shulevski, M. Brienza, F. Massaro +15
We present the discovery of a very extended (550 kpc) and low-surface-brightness ( at 144 MHz) radio emission region in Abell 1318. These proper…
Apertif, Phased Array Feeds for the Westerbork Synthesis Radio Telescope
W. A. van Cappellen, T. A. Oosterloo, M. A. W. Verheijen +87
We describe the APERture Tile In Focus (Apertif) system, a phased array feed (PAF) upgrade of the Westerbork Synthesis Radio Telescope which has transformed this telescope into a h…
Apertif 1.4 GHz continuum observations of the Boötes field and their combined view with LOFAR
A. M. Kutkin, T. A. Oosterloo, R. Morganti +17
We present a new image of a 26.5 square degree region in the Boötes constellation obtained at 1.4 GHz using the Aperture Tile in Focus (Apertif) system on the Westerbork Synthesis…
A search for radio emission from double-neutron star merger GW190425 using Apertif
Olivér Boersma, Joeri van Leeuwen, Elizabeth A. K. Adams +26
Detection of the electromagnetic emission from coalescing binary neutron stars (BNS) is important for understanding the merger and afterglow. We present a search for a radio counte…
An interference detection strategy for Apertif based on AOFlagger 3
A. R. Offringa, B. Adebahr, A. Kutkin +15
Context. Apertif is a multi-beam receiver system for the Westerbork Synthesis Radio Telescope that operates at 1.1-1.5 GHz, which overlaps with various radio services, resulting in…
A Square Kilometre Array Pulsar Census
E. F. Keane, V. Graber, L. Levin +7
Most of the pulsar science case with the Square Kilometre Array (SKA) depends on long-term precision timing of a large number of pulsars, as well as their astrometric measurements…
Extreme intra-hour variability of the radio source J1402+5347 discovered with Apertif
T. A. Oosterloo, H. K. Vedantham, A. M. Kutkin +27
The propagation of radio waves from distant compact radio sources through turbulent interstellar plasma in our Galaxy causes these sources to twinkle, a phenomenon called interstel…
Survey-scale discovery-based research processes: Evaluating a bespoke visualisation environment for astronomical survey data
C. J. Fluke, D. Vohl, V. A. Kilborn +1
Next generation astronomical surveys naturally pose challenges for human-centred visualisation and analysis workflows that currently rely on the use of standard desktop display env…
First release of Apertif imaging survey data
Elizabeth A. K. Adams, B. Adebahr, W. J. G. de Blok +56
(Abridged) Apertif is a phased-array feed system for WSRT, providing forty instantaneous beams over 300 MHz of bandwidth. A dedicated survey program started on 1 July 2019, with th…
Characterising the Apertif primary beam response
H. Dénes, K. M. Hess, E. A. K. Adams +27
Context. Phased Array Feeds (PAFs) are multi element receivers in the focal plane of a telescope that make it possible to form simultaneously multiple beams on the sky by combining…
Dual-frequency single-pulse study of PSR B0950+08
A. V. Bilous, J. M. Griessmeier, T. Pennucci +33
PSR B0950+08 is a bright non-recycled pulsar whose single-pulse fluence variability is reportedly large. Based on observations at two widely separated frequencies, 55 MHz (NenuFAR)…
Apercal -- The Apertif Calibration Pipeline
B. Adebahr, R. Schulz, T. J. Dijkema +33
Apertif (APERture Tile In Focus) is one of the Square Kilometre Array (SKA) pathfinder facilities. The Apertif project is an upgrade to the 50-year-old Westerbork Synthesis Radio T…
Searching for FRB persistent radio source counterparts in dwarf galaxies using LOFAR
D. Vohl, H . K. Vedantham, J. W. T. Hessels +1
The repeating FRB 20121102A was localized to a star-forming region in a dwarf galaxy and found to be co-located with a persistent radio source (PRS). FRB 20190520B is only the seco…
Understanding Pulsar Magnetospheres with the SKAO
L. S. Oswald, A. Basu, M. Chakraborty +21
The SKA telescopes will bring unparalleled sensitivity across a broad radio band, a wide field of view across the Southern sky, and the capacity for sub-arraying, all of which make…
Topology of Pulsar Profiles (ToPP). I. Graph theory method and classification of the EPN
D. Vohl, J. van Leeuwen, Y. Maan
Some of the most important information on a radio pulsar is derived from its average pulse profile. Many early pulsar studies were necessarily based on only few such profiles. Ther…
Repeating fast radio bursts with WSRT/Apertif
L. C. Oostrum, Y. Maan, J. van Leeuwen +40
Repeating fast radio bursts (FRBs) present excellent opportunities to identify FRB progenitors and host environments, as well as decipher the underlying emission mechanism. Detaile…
The Apertif science verification campaign - Characteristics of polarised radio sources
B. Adebahr, A. Berger, E. A. K. Adams +24
We analyse five early science datasets from the APERture Tile in Focus (Apertif) phased array feed system to verify the polarisation capabilities of Apertif in view of future large…
Continuum source catalog for the first APERTIF data release
A. M. Kutkin, T. A. Oosterloo, R. Morganti +25
The first data release of Apertif survey contains 3074 radio continuum images covering a thousand square degrees of the sky. The observations were performed during August 2019 to J…
A LOFAR sample of luminous compact sources coincident with nearby dwarf galaxies
D. Vohl, H. K. Vedantham, J. W. T. Hessels +5
The vast majority of extragalactic compact continuum radio sources are associated with star formation or jets from (super)massive black holes and, as such, are more likely to be fo…