* Astronomy

Title: The faintest radio source yet: EVLA observations of the gravitational lens SDSS J1004+4112
Authors: 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 Array (EVLA). The maps reach a thermal noise level of approximately 4microJy. We detect four of the five lensed images at the 15-35microJy level, representing a source of intrinsic flux density, after allowing for lensing magnification, of about 1microJy, intrinsically probably the faintest radio source yet detected. This reinforces the utility of gravitational lensing in potentially allowing us to study nanoJy-level sources before the advent of the SKA. In an optical observation taken three months after the radio observation, image C is the brightest image, whereas the radio map shows flux density ratios consistent with previous optical observations. Future observations separated by a time delay will give the intrinsic flux ratios of the images in this source.

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