| Description: | Gravitational lensing is the deflection of light from a distant background object (the source) by an intervening mass distribution (the lens). If the surface mass density of the lens is sufficiently high, then multiple images of the background source, which are often highly magnified and distorted, are produced. The gravitational lensing phenomena is beautifully illustrated in this global very long baseline interferometry image of JVAS B1938+666 at redshift 2.059. Here, the extended background radio source is highly distorted into a gravitational arc. Never before has an extended gravitational arc been seen with such detail, which highlights the excellent sensitivity that can be achieved with VLBI arrays today (a collecting area that is about 10 per cent of the proposed SKA).
The image was made from a 22 hour observation with an array that included 11 stations from the EVN, 7 stations from the VLBA and the GBT. The image noise is about 30 uJy / beam and the resolution is about 4 x 2 mas. The maximum separation of the images is about 1 arcsecond. |
