Related papers: The gravitational lens J1131-1231 - How to avoid m…
The VLBA was used at 1.6 GHz to observe a target field 50 arcminutes in diameter including the core of M31. Novel VLBI correlation techniques were used to observe 200 sources simultaneously, of which 16 were detected. We classify all 16 as…
Similarly to light, gravitational waves can be gravitationally lensed as they propagate near massive astrophysical objects such as galaxies, stars, or black holes. In recent years, forecasts have suggested a reasonable chance of strong…
We present evidence that the optically unidentified radio source, FIRST J121839.7+295325, may be strongly lensing a background galaxy. We estimate the redshift of the assumed gravitational arc, discovered in parallel imaging with HST, from…
We report the detection of molecular absorption lines at z=0.7645 towards the radio-loud QSO PMN 0134-0931. The CO J=2-1 and HCO+ J=2-1 lines are seen in absorption along two different lines of sight to lensed images of the background QSO.…
Submillimetre-selected galaxies (SMGs) at high redshift ($z$ $\sim$ 2) are potential host galaxies of active galactic nuclei (AGN). If the local Universe is a good guide, $\sim$ 50$\%$ of the obscured AGN amongst the SMG population could be…
Gravitational lensing is a powerful astrophysical and cosmological probe and is particularly valuable at submillimeter wavelengths for the study of the statistical and individual properties of dusty starforming galaxies. However the…
We observed the quadruple gravitationally lensed image of MGJ0414+0534 on 23 November 1997 with a global VLBI array at 8.4 GHz. We report wide-field imaging results of its four components at submilliarcsecond resolution, displaying complex…
When gravitational waves pass near massive astrophysical objects, they can be gravitationally lensed. The lensing can split them into multiple wave-fronts, magnify them, or imprint beating patterns on the waves. Here we focus on the…
We present the results from nine years of optically monitoring the gravitationally lensed z=0.658 quasar RX J1131-1231. The R-band light curves of the four individual images of the quasar were obtained using deconvolution photometry for a…
We discuss the gravitational lensing of gravitational wave signals from coalescing binaries. We delineate the regime where wave effects are significant from the regime where geometric limit can be used. Further, we focus on the effect of…
We present the first unambiguous case of external variability of an extra-galactic radio source, the CLASS gravitational lens B1600+434, consisting of two images lensed by an edge-on disk galaxy. The VLA 8.5-GHz difference light curve of…
Strong lensing gravitational time delays are a powerful and cost effective probe of dark energy. Recent studies have shown that a single lens can provide a distance measurement with 6-7 % accuracy (including random and systematic…
We present multi-frequency radio continuum VLBI observations of the gravitational lens system B0218+357 carried out using a global VLBI network and the VLBA. The source has been observed with resolutions from 0.2 milliarcsec to 5…
We report multiwavelength observations of the gravitationally lensed blazar QSO B0218+357 in 2016-2020. Optical, X-ray and GeV flares were detected. The contemporaneous MAGIC observations do not show significant very-high-energy (VHE, >=…
Multimessenger astronomy incorporating gravitational radiation is a new and exciting field that will potentially provide significant results and exciting challenges in the near future. With advanced interferometric gravitational wave…
We study the faint radio population using wide-field very long baseline interferometry (VLBI) observations of 2865 known radio sources in the Cosmic Evolution Survey (COSMOS) field. The main objective of the project was to determine where…
We present wide-field images of the quadruple gravitational lenses B1422+231 and MGJ0414+0534 obtained from global Very Long Baseline Interferometry (VLBI) observations at 8.4 GHz on 23 November 1997. We present also a lens model for…
We present observations of CLASS B2108+213, the widest separation gravitational lens system discovered by the Cosmic Lens All-Sky Survey. Radio imaging using the VLA at 8.46 GHz and MERLIN at 5 GHz shows two compact components separated by…
The cold dark matter scenario of hierarchical large-scale structure formation predicts the existence of abundant subhalos around large galaxies. However, the number of observed dwarf galaxies is far from this theoretical prediction,…
The centres of galaxies are powerful laboratories to test the current $\Lambda$CDM model for structure formation and evolution. While these sub-galactic scales can be directly investigated in the local Universe, it is observationally…