A 325-MHz GMRT survey of the Herschel-ATLAS/GAMA fields
  We describe a 325-MHz survey, undertaken with the Giant Metrewave Radio
Telescope (GMRT), which covers a large part of the three equatorial fields at
9, 12 and 14.5 h of right ascension from the Herschel-Astrophysical Terahertz
Large Area Survey (H-ATLAS) in the area also covered by the Galaxy And Mass
Assembly survey (GAMA). The full dataset, after some observed pointings were
removed during the data reduction process, comprises 212 GMRT pointings
covering ~90 deg^2 of sky. We have imaged and catalogued the data using a
pipeline that automates the process of flagging, calibration, self-calibration
and source detection for each of the survey pointings. The resulting images
have resolutions of between 14 and 24 arcsec and minimum rms noise (away from
bright sources) of ~1 mJy/beam, and the catalogue contains 5263 sources
brighter than 5 sigma. We investigate the spectral indices of GMRT sources
which are also detected at 1.4 GHz and find them to agree broadly with
previously published results; there is no evidence for any flattening of the
radio spectral index below S_1.4=10 mJy. This work adds to the large amount of
available optical and infrared data in the H-ATLAS equatorial fields and will
facilitate further study of the low-frequency radio properties of star
formation and AGN activity in galaxies out to z~1.
