Observations of Gravitational Lens Central Images


We request observations to search for central core images in two gravitational lenses. Gravitational lenses may include a faint core image, whose brightness depends on the density profile in the central region: a steeper profile in the central region generates a fainter image. For each system, a detection or upper limit on the core image flux will determine whether the core is large and relatively shallow, or smaller and steeper. Confusion of the core image and the lens galaxy in the optical regime requires core image observations to be made in the radio. The core image is expected to be faint and located 30-100 mas from a much brighter lens image, so the angular resolution of VLBI and the high sensitivity of the HSA is required.

Name Other * Institution Email Phone
Edward Boyce PI T JBO
Jackie Hewitt Massachusetts Institute of Tec 617 253-3071 5628,fax:617 258-7864
Steve Myers NRAO -SOC 505-835-7294
* PI = Principal Investigator; CO = Contact author; T = Thesis observations; S = Student

Front Ends
Gregorian C(3.95 to 5.85 GHz) Gregorian X(8.2 to 10.0 GHz)

Back Ends
VLBA recorder and DAR

Type of Observing
Very Long Baseline Interferometry

Switching Type

Processor (correlator)

Allotted time 5.50 hours

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Updated 09/19/2007