276 citations · 882 across the 25 of their papers we have counts for
25 papers
Very Long Baseline Interferometry with the SKA Observatory
J. F. Radcliffe, J. Yang, Z. Paragi +129
Very Long Baseline Interferometry (VLBI) is a fundamental technique that combines signals from telescopes separated by thousands of kilometres to obtain some of the highest-resolut…
Spectral indices in active galactic nuclei as seen by Apertif and LOFAR
A. M. Kutkin, R. Morganti, T. A. Oosterloo +5
We present two new radio continuum images obtained with Apertif at 1.4 GHz. The images, produced with a direction-dependent calibration pipeline, cover 136 square degrees of the Lo…
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…
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…
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…
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…
Seeing the forest and the trees: a radio investigation of the ULIRG Mrk 273
Pranav Kukreti, Raffaella Morganti, Marco Bondi +19
Galaxy mergers have been observed to trigger nuclear activity by feeding gas to the central supermassive black hole. One such class of objects are Ultra Luminous InfraRed Galaxies…
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…
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…
Combining LOFAR and Apertif Data for Understanding the Life Cycle of Radio Galaxies
Raffaella Morganti, Nika Jurlin, Tom Oosterloo +10
Active galactic nuclei (AGN) at the centres of galaxies can cycle between periods of activity and of quiescence. Characterising the duty-cycle of AGN is crucial for understanding t…
Radio and -ray activity in the jet of the blazar S5 0716714
Dae-Won Kim, Evgeniya V. Kravchenko, Alexander M. Kutkin +11
We explore the connection between the -ray and radio emission in the jet of the blazar 0716714 by using 15, 37, and 230 GHz radio and 0.1200 GeV -ray light curves spann…
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)…
Parabolic jet shape on parsec scales in high redshift AGN
E. E. Nokhrina, I. N. Pashchenko, A. M. Kutkin
Geometry of relativistic jets in active galaxies provides important information about mechanisms of launching, collimation and acceleration of plasma flow. We propose a new method…
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…
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…
Chromatic periodic activity down to 120 MHz in a Fast Radio Burst
Inés Pastor-Marazuela, Liam Connor, Joeri van Leeuwen +34
Fast radio bursts (FRBs) are extragalactic astrophysical transients whose brightness requires emitters that are highly energetic, yet compact enough to produce the short, milliseco…
A bias in VLBI measurements of the core shift effect in AGN jets
I. N. Pashchenko, A. V. Plavin, A. M. Kutkin +1
The Blandford and Königl model of AGN jets predicts that the position of the apparent opaque jet base - the core - changes with frequency. This effect is observed with radio interf…
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…
A bright, high rotation-measure FRB that skewers the M33 halo
Liam Connor, Joeri van Leeuwen, L. C. Oostrum +37
We report the detection of a bright fast radio burst, FRB\,191108, with Apertif on the Westerbork Synthesis Radio Telescope (WSRT). The interferometer allows us to localise the FRB…
Detection statistics of the RadioAstron AGN survey
Y. Y. Kovalev, N. S. Kardashev, K. V. Sokolovsky +57
The largest Key Science Program of the RadioAstron space VLBI mission is a survey of active galactic nuclei (AGN). The main goal of the survey is to measure and study the brightnes…
Opacity, variability and kinematics of AGN jets
Alexander Kutkin, Ilya Pashchenko, Kirill Sokolovsky +3
Synchrotron self-absorption in active galactic nuclei (AGN) jets manifests itself as a time delay between flares observed at high and low radio frequencies. It is also responsible…
The high brightness temperature of B0529+483 revealed by RadioAstron and implications for interstellar scattering
S. V. Pilipenko, Y. Y. Kovalev, A. S. Andrianov +22
The high brightness temperatures, K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. R…
Probing the gravitational redshift with an Earth-orbiting satellite
D. A. Litvinov, V. N. Rudenko, A. V. Alakoz +45
We present an approach to testing the gravitational redshift effect using the RadioAstron satellite. The experiment is based on a modification of the Gravity Probe A scheme of nonr…
The core shift effect in the blazar 3C 454.3
A. M. Kutkin, K. V. Sokolovsky, M. M. Lisakov +10
Opacity-driven shifts of the apparent VLBI core position with frequency (the "core shift" effect) probe physical conditions in the innermost parts of jets in active galactic nuclei…