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Australia Telescope Low-Brightness Survey Source Catalog

Listed in NASA Data Portal

The Australia Telescope Low-brightness Survey (ATLBS) regions have been mosaic imaged at a radio frequency of 1.4 GHz with 6 arcseconds angular resolution and 72 microJansky per beam (µJy/beam) rms noise.

Description

The images (centered at RA 00<sup>h</sup> 35<sup>m</sup> 00<sup>s</sup>, Dec -67<sup>o</sup> 00' 00" and RA 00<sup>h</sup> 59<sup>m</sup> 17<sup>s</sup>, Dec -67<sup>o</sup> 00' 00", J2000 epoch) cover 8.42 deg<sup>2</sup> sky area and have no artifacts or imaging errors above the image thermal noise.

Multi-resolution radio and optical r-band images (made using the 4 m CTIO Blanco telescope) were used to recognize multi-component sources and prepare a source list of 1366 1.4-GHZ sources; the detection threshold was 0.38 mJy in a low-resolution radio image made with beam FWHM of 50 arcseconds. Radio source counts in the flux density range 0.4-8.7 mJy are estimated, with corrections applied for noise bias, effective area correction, and resolution bias.

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The resolution bias is mitigated using low-resolution radio images, while effects of source confusion are removed by using high-resolution images for identifying blended sources. Below 1 mJy the ATLBS counts are systematically lower than the previous estimates. Showing no evidence for an upturn down to 0.4 mJy, they do not require any changes in the radio source population down to the limit of the survey.

The work suggests that automated image analysis for counts may be dependent on the ability of the imaging to reproduce connecting emission with low surface brightness and on the ability of the algorithm to recognize sources, which may require that source finding algorithms effectively work with multi-resolution and multi-wavelength data. The work underscores the importance of using source lists - as opposed to component lists - and correcting for the noise bias in order to precisely estimate counts close to the image noise and determine the upturn at sub-mJy flux density.

This table was created by the HEASARC in April 2013 based on an electronic version of Table 2 from the reference paper that was obtained from the ApJ web site.. This is a service provided by NASA HEASARC .

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Inferred from text
Image 75% · Imaging 75% · Tabular 65%
Provenance · 1 source records, 9 field assertions
SourceKeyLast seenRaw
NASA Data Portalfb95bd07-c606-4db3-9d2b-5cbd0367496c11 d agoJSON v1
FieldAssertionExtractorEvidence
concepts[modality].local:modality:imageenrichment · data nasa govkeyword-concept-rules@1.0.0title+description (75%)
concepts[modality].local:modality:imagingenrichment · data nasa govkeyword-concept-rules@1.0.0title+description (75%)
concepts[modality].local:modality:tabularenrichment · data nasa govkeyword-concept-rules@1.0.0title+description (65%)
created_datesource · data nasa govconnector:data_nasa_gov@1.0.0
descriptionsource · data nasa govconnector:data_nasa_gov@1.0.0/notes
license_textsource · data nasa govconnector:data_nasa_gov@1.0.0
publication_datesource · data nasa govconnector:data_nasa_gov@1.0.0
titlesource · data nasa govconnector:data_nasa_gov@1.0.0/title
updated_datesource · data nasa govconnector:data_nasa_gov@1.0.0