Publications (34)
Radio imaging of gravitationally lensed radio-quiet quasars
Neal Jackson, Shruti Badole, Thomas Dugdale +4
We present 6-GHz Very Large Array radio images of 70 gravitational lens systems at 300-mas resolution, in which the source is an optically-selected quasar, and nearly all of which…
New lensed quasars from the MUSCLES survey
Neal Jackson, Hayden Rampadarath, Eran O. Ofek +2
Gravitational lens systems containing lensed quasars are important as cosmological probes, as diagnostics of structural properties of the lensing galaxies and as tools to study the…
Near-infrared spectroscopy of powerful compact steep-spectrum radio sources
Paul Hirst, Neal Jackson, Steve Rawlings
We have obtained near-infrared spectroscopy of a small sample of powerful Compact Steep-Spectrum (CSS) radio sources mainly, but not exclusively, from the 3CR sample. We find no di…
A decade of sub-arcsecond imaging with the International LOFAR Telescope
Leah K. Morabito, Neal Jackson, Jurjen de Jong +7
The International LOFAR Telescope (ILT) is a pan-European radio interferometer with baselines up to 2,000 km. This provides sub-arcsecond resolution at frequencies of <200 MHz. Sin…
Gravitational lenses and lens candidates identified from the COSMOS field
Neal Jackson
A complete manual search has been carried out of the list of 285423 objects, nearly all of them galaxies, identified in the COSMOS field that are brighter than I=25. Two certain an…
A new VLA/e-MERLIN limit on central images in the gravitational lens system CLASS B1030+074
Jonathan Quinn, Neal Jackson, Amitpal Tagore +8
We present new VLA 22-GHz and e-MERLIN 5-GHz observations of CLASS B1030+074, a two-image strong gravitational lens system whose background source is a compact flat-spectrum radio…
Quasar lensing
Neal Jackson
I review the observations of gravitationally lensed quasars. These systems are important because they allow us to probe the properties of the lensing galaxies at various scales, an…
High-resolution imaging with the International LOFAR Telescope: Observations of the gravitational lenses MG 0751+2716 and CLASS B1600+434
Shruti Badole, Deepika Venkattu, Neal Jackson +7
We present Low-Frequency Array (LOFAR) telescope observations of the radio-loud gravitational lens systems MG 0751+2716 and CLASS B1600+434. These observations produce images at 30…
LOFAR and APERTIF surveys of the radio sky: probing shocks and magnetic fields in galaxy clusters
Huub Rottgering, Jose Afonso, Peter Barthel +32
At very low frequencies, the new pan-European radio telescope LOFAR is opening the last unexplored window of the electromagnetic spectrum for astrophysical studies. The revolutiona…
LOFAR: Early imaging results from commissioning for Cygnus A
John McKean, Louise Ker, Reinout J. van Weeren +19
The Low Frequency Array (LOFAR) will operate between 10 and 250 MHz, and will observe the low frequency Universe to an unprecedented sensitivity and angular resolution. The constru…
Spectral analysis of spatially-resolved 3C295 (sub-arcsecond resolution) with the International LOFAR Telescope
Etienne Bonnassieux, Frits Sweijen, Marisa Brienza +11
3C295 is a bright, compact steep spectrum source with a well-studied integrated radio spectral energy distribution (SED) from 132 MHz to 15 GHz. However, spatially resolved spectra…
SuperCLASS -- II: Photometric Redshifts and Characteristics of Spatially-Resolved Jy Radio Sources
Sinclaire M. Manning, Caitlin M. Casey, Chao-Ling Hung +12
We present optical and near-infrared imaging covering a 1.53 deg region in the Super-Cluster Assisted Shear Survey (SuperCLASS) field, which aims to make the first robust…
Unmasking the history of 3C 293 with LOFAR sub-arcsecond imaging
Pranav Kukreti, Raffaella Morganti, Timothy W. Shimwell +10
Active galactic nuclei (AGNs) show episodic activity, evident in galaxies that exhibit restarted radio jets. These restarted jets can interact with their environment, leaving signa…
The impact of human expert visual inspection on the discovery of strong gravitational lenses
Karina Rojas, Thomas E. Collett, Daniel Ballard +53
We investigate the ability of human 'expert' classifiers to identify strong gravitational lens candidates in Dark Energy Survey like imaging. We recruited a total of 55 people that…
A new gravitational lens from the MUSCLES survey: ULAS J082016.1+081216
Neal Jackson, Eran O. Ofek, Masamune Oguri
We present observations of a new double-image gravitational lens system, ULAS J082016.1+081216, of image separation 2.3" and high (~6) flux ratio. The system is selected from the S…
Limits on global cosmic birefringence using radio sources
Richard A. Battye, Neal Jackson, Ian Browne
We have made measurements of the difference between the position angle (PA) on the sky and the polarization position angle (PPA) of radio sources using data from a combination of t…
On the use of shapelets in modelling resolved, gravitationally lensed images
Amitpal S. Tagore, Neal Jackson
Lens modeling of resolved image data has advanced rapidly over the past two decades. More recently pixel-based approaches, wherein the source is reconstructed on an irregular or ad…
LOFAR: Recent imaging results & future prospects
George Heald, Michael R. Bell, Andreas Horneffer +27
The Low Frequency Array (LOFAR) is under construction in the Netherlands and in several surrounding European countries. In this contribution, we describe the layout and design of t…
Reducing biases on measurements using strong lensing and galaxy dynamics: results from the EAGLE simulation
Amitpal S. Tagore, David J. Barnes, Neal Jackson +4
Cosmological parameter constraints from observations of time-delay lenses are becoming increasingly precise. However, there may be significant bias and scatter in these measurement…
LOFAR VLBI Studies at 55 MHz of 4C 43.15, a z=2.4 Radio Galaxy
Leah K. Morabito, Adam T. Deller, Huub Röttgering +8
The correlation between radio spectral index and redshift has been exploited to discover high redshift radio galaxies, but its underlying cause is unclear. It is crucial to charact…
Strong Lens Time Delay Challenge: II. Results of TDC1
Kai Liao, Tommaso Treu, Phil Marshall +23
We present the results of the first strong lens time delay challenge. The motivation, experimental design, and entry level challenge are described in a companion paper. This paper…
Sub-arcsecond imaging with the International LOFAR Telescope: II. Completion of the LOFAR Long-Baseline Calibrator Survey
Neal Jackson, Shruti Badole, John Morgan +69
The Low-Frequency Array (LOFAR) Long-Baseline Calibrator Survey (LBCS) was conducted between 2014 and 2019 in order to obtain a set of suitable calibrators for the LOFAR array. In…
ULAS J234311.93-005034.0: A gravitational lens system selected from UKIDSS and SDSS
Neal Jackson, Eran O. Ofek, Masamune Oguri
We report the discovery of a new gravitational lens system. This object, ULAS J234311.93-005034.0, is the first to be selected by using the new UKIRT Infrared Deep Sky Survey (UKID…
A Pilot Study for the SCUBA-2 'All-Sky' Survey
Todd Mackenzie, Filiberto G. Braglia, Andy G. Gibb +30
We have carried out a pilot study for the SCUBA-2 'All-Sky' Survey, SASSy, a wide and shallow mapping project at 850 microns, designed to find rare objects, both Galactic and extra…
The faintest radio source yet: EVLA observations of the gravitational lens SDSS J1004+4112
Neal Jackson
We present new radio observations of the large-separation gravitationally-lensed quasar SDSS J1004+4112, taken in a total of 6 hours of observations with the Extended Very Large Ar…
The Hubble Constant
Neal Jackson
I review the current state of determinations of the Hubble constant, which gives the length scale of the Universe by relating the expansion velocity of objects to their distance. T…
A search for distant radio-loud quasars in the CLASS survey: three new radio-selected quasars at z>4
Ignas Snellen, Richard McMahon, Jane Dennett-Thorpe +3
We report on the search for distant radio-loud quasars in the Cosmic Lens All Sky Survey (CLASS) of flat spectrum radio sources with S_5GHz>30 mJy. Unresolved optical counterparts…
Synergy between the Large Synoptic Survey Telescope and the Square Kilometre Array
David Bacon, Sarah Bridle, Filipe B. Abdalla +18
We provide an overview of the science benefits of combining information from the Square Kilometre Array (SKA) and the Large Synoptic Survey Telescope (LSST). We first summarise the…
High-resolution international LOFAR observations of 4C~43.15 -- Spectral ages and injection indices in a high-z radio galaxy
Frits Sweijen, Leah K. Morabito, Jeremy Harwood +6
Radio sources with steep spectra are preferentially associated with the most distant galaxies, the relation, but the reason for this relation is an open question. The spatia…
The Strong Gravitational Lens Finding Challenge
R. Benton Metcalf, M. Meneghetti, Camille Avestruz +33
Large scale imaging surveys will increase the number of galaxy-scale strong lensing candidates by maybe three orders of magnitudes beyond the number known today. Finding these rare…
Quasar emission lines, radio structures and radio unification
Neal Jackson, I. W. A. Browne
Unified schemes of radio sources, which account for different types of radio AGN in terms of anisotropic radio and optical emission, together with different orientations of the eje…
The Signpost Platform for City-Scale Sensing
Joshua Adkins, Branden Ghena, Neal Jackson +4
City-scale sensing holds the promise of enabling a deeper understanding of our urban environments. However, a city-scale deployment requires physical installation, power management…
The Herschel-SPIRE Legacy Survey (HSLS): the scientific goals of a shallow and wide submillimeter imaging survey with SPIRE
Asantha Cooray, Steve Eales, Scott Chapman +247
A large sub-mm survey with Herschel will enable many exciting science opportunities, especially in an era of wide-field optical and radio surveys and high resolution cosmic microwa…
Observations of radio-quiet quasars at 10mas resolution by use of gravitational lensing
Neal Jackson, Amitpal S. Tagore, Carl Roberts +5
We present VLA detections of radio emission in four four-image gravitational lens systems with quasar sources: HS0810+2554, RXJ0911+0511, HE04351223 and SDSSJ0924+0219, and e-ME…