Faint Radio Sources in the NOAO Bootes Field
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.
Legacy Astronomical Images
NRAO/AUI/NSF does not hold full copyright for this image. Contact the archivist for details.
Legacy Astronomical Image
J.M. Wrobel, G.B. Taylor, T.A. Rector, S.T. Myers, C.D. Fassnacht
Very Long Baseline Array (VLBA)
Type of Observation
Center of Image
RA 14:32:5.720, Dec: 34:16:47.500 (J2000)
Field of View
3.000000 x 3.000000 degrees
Contact the archivist for a high resolution tif of this image.
Active Galactic Nuclei Series
Radio Galaxies Unit
Legacy Astronomical Images, “Faint Radio Sources in the NOAO Bootes Field,” NRAO Archives, accessed December 4, 2021, https://www.nrao.edu/archives/items/show/33357.