NRAO: National Radio Astronomy Observatory

About this Image

As a step toward investigating the properties of faint extragalactic sources on light-year scales, the VLBA was used at 5.0 GHz to survey 76 sources in the NOAO Bootes field. The image shows the geometry for the VLBA survey, the largest of its kind to date. The Bootes field covers the 9 square degrees shown as yellow in the image. The circles within the Bootes field mark the locations of the 76 faint radio sources. The squares beyond the Bootes field locate calibrator sources, four of which served as "phase calibrators" for the VLBA observations of the faint radio sources within the large dashed circles, each of radius 2.5 degrees. About forty percent of the faint radio sources were detected with the VLBA at an angular resolution of 0.002 arcsec, corresponding to 60 light years or less for a WMAP cosmology. Most VLBA detections are unresolved or slightly resolved, but one is diffuse and five show either double or core-jet structures. Three VLBA detections are unidentified in the near infrared and likely mark optically obscured active nuclei in the distant universe.

Investigator(s):  J.M. Wrobel, G.B. Taylor, T.A. Rector, S.T. Myers, and C.D. Fassnacht

Alternate Resolutions

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This image is available in the following downloadable versions:

• 546 x 457 color JPEG
• 922 x 772 color JPEG
• 2049 x 1715 color TIFF

If you would like to obtain a higher resolution version of this image, please contact Pat Smiley.

For More Information

• Read the Journal article
• Up one level for more info on Radio_Galaxies
• For unfamiliar terms, visit the NRAO Radio Astronomy Glossary

Technical Data

Telescope	VLBA
Date of Observation	2002-06-15
Type of Observation	Continuum Observations
Band	C
Wavelength	6 cm
Frequency	5.0 GHz
Center of Image	RA: 14:32:5.72, Dec: 34:16:47.50 (J2000)
Field of View	3.0000 x 3.0000 degrees



Astronomical database entries for Bootes field
• Query NED for images of Bootes field
• Query SIMBAD for more Bootes field data

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