ATLASD2CPT - AT Large Area Survey (ATLAS) CDF-S & ELAIS-S1 1.4-GHz DR2 Components Catalog

Overview

This table derives from the first of two papers describing the second data release (DR2) of the Australia Telescope Large Area Survey (ATLAS) at 1.4 GHz. This survey comprises deep wide-field observations in total intensity, linear polarization, and circular polarization over the Chandra Deep Field-South (CDF-S) and European Large Area Infrared Space Observatory Survey (ELAIS)-South 1 regions. DR2 improves upon the first data release by maintaining consistent data reductions across the two regions, including polarization analysis, and including differential number counts in total intensity and linear polarization. Typical DR2 sensitivities across the mosaicked multi-pointing images are 30 µJy per beam at approximately 12 arcseconds by 6 arcseconds resolution over a combined area of 6.4 square degrees. In their paper, the authors present detailed descriptions of their data reduction and analysis procedures, including corrections for instrumental effects such as positional variations in image sensitivity, bandwidth smearing with a non-circular beam, and polarization leakage, and application of the BLOBCAT source extractor. They present the DR2 images and catalogs of components (discrete regions of radio emission) and sources (groups of physically associated radio components), and describe new analytic methods to account for resolution bias and Eddington bias when constructing differential number counts of radio components.

The authors use the term 'component' to refer to an isolated region of emission that is best described by a single 2D elliptical Gaussian. Blended regions of contiguous emission may consist of multiple individual components. Following the terminology from Hales et al. (2012, MNRAS, 425, 979), a 'blob' is an agglomerated island of pixels above an SNR cutoff, which may encapsulate a single component or a blended region of emission. In Section 6 of the reference paper, the authors use the term 'source' to refer to single or multiple components belonging to the same astronomical object.

This HEASARC table contains the ATLAS 1.4 GHz DR2 component catalog, a portion of which is displayed in Table A1 of the reference paper for guidance regarding its form and content. The catalog lists a total of 2,588 components in total intensity and linear polarization; no components were discovered in circular polarization. A list of the ATLAS 1.4 GHz DR2 sources, a portion of which is displayed in Table B1 of the reference paper for guidance regarding its form and content, is not included in this HEASARC table.

Catalog Bibcode

2014MNRAS.441.2555H

References

ATLAS 1.4 GHz Data Release 2 - I. Observations of the CDF-S and ELAIS-S1 fields
and methods for constructing differential number counts

   Hales C.A., Norris R.P., Gaensler B.M., Middelberg E., Chow K.E.,
   Hopkins A.M., Huynh M.T., Lenc E., Mao M.Y.
   <Mon. Not. Royal Astr. Soc. 441, 2555 (2014)>
   =2014MNRAS.441.2555H

Provenance

This table was created by the HEASARC in October 2014 based on an electronic version of Table A1 from the reference paper which was obtained from the MNRAS web site.

Parameters

Source_ID
The component identification number. This gives the internal designation of the component used within the data processing. The form is a composite of three descriptors plus an optional fourth. The first is a single character that represents the ATLAS field, given by C for CDF-S or E for ELAIS-S1. The second descriptor is a single character that represents the nature of detection, given by T for total intensity or L for linear polarization. The third descriptor is an integer that gives the blob identification number assigned by BLOBCAT (cf. Section 5.1 of the reference paper). The fourth descriptor is only suffixed for those components that were obtained through refitting all or part of the original blob using IMFIT, denoted by C_j, or BLOBCAT, denoted by F_j, for the jth extracted component from a given blob.

Name
The full ATLAS DR2 component name. This has been provided in a form acceptable for International Astronomical Union (IAU) designation (Lortet, Borde & Ochsenbein 1994, A&AS, 107, 193). The form is 'ATLAS2 JHHMMSS.ss+DDMMSS.sC', where ATLAS2 is the survey acronym, 'J' specifies the J2000.0 coordinate equinox, 'HHMMSS.ss' are the hours, minutes and truncated (not rounded) seconds of Right Ascension, '+' or '-' is the sign of the Declination, 'DDMMSS.s' are the degrees, arcminutes and truncated arcseconds of the Declination, and the final single character specifier 'C' indicates the nature of the detection as 'T' (total intensity) or 'L' (linear polarization). Note that that the HEASARC has removed the '_' character that was included in these names by the authors, viz., 'ATLAS2_JHHMMSS.ss+DDMMSS.sC'.

RA
The Right Ascension of the intensity-weighted centroid of the 1.4-GHz component in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-6 degrees in the original table.

Dec
The Declination of the intensity-weighted centroid of the 1.4-GHz component in the selected equinox. This was given in J2000.0 decimal degrees to a precision of 10^-6 degrees in the original table.

LII
The Galactic Longitude of the intensity-weighted centroid of the 1.4-GHz component.

BII
The Galactic Latitude of the intensity-weighted centroid of the 1.4-GHz component.

RA_Error
The absolute astrometric uncertainty in RA, in arcseconds. The minimum and maximum errors are 0.11 and 1.1 arcseconds in Right Ascension, and 0.17 and 2.1 arcseconds in Declination, respectively.

Dec_Error
The absolute astrometric uncertainty in Declination, in arcseconds. The minimum and maximum errors are 0.11 and 1.1 arcseconds in Right Ascension, and 0.17 and 2.1 arcseconds in Declination, respectively.

SNR
The signal-to-noise ratio of the raw detection of the 1.4-GHz component.

RMS_1p4_GHz
The local rms noise value, in mJy/beam, near the radio component.

Bws_Value
The local bandwidth smearing (chromatic aberration) value at the position of the radio component, cf. Section 4.2 of the reference paper.

Flux_1p4_GHz
The peak surface brightness (S_peak) of the 1.4-GHz component corrected for the effect of bandwidth smearing, in mJy/beam.

Flux_1p4_GHz_Error
The rms error in the peak surface brightness of the 1.4-GHz component corrected for the effect of bandwidth smearing, in mJy/beam.

Int_Flux_1p4_GHz
The integrated surface brightness (S_int) of the 1.4-GHz component, in mJy.

Int_Flux_1p4_GHz_Error
The rms error in the integrated surface brightness of the 1.4-GHz component, in mJy.

Visibility_Area
The visibility area for the 1.4-GHz component. This is the fraction of the survey area over which the blob could have been detected due to rms noise and bandwidth smearing fluctuations.

Angular_Size_Limit
If the 1.4-GHz component is not resolved, this parameter is set to '<'.

Angular_Size
The estimated deconvolved angular size (or upper bound thereof if the parameter angular_size_limit = '<'), Theta, in arcseconds. If the angular-size_error value is not null, then the component is resolved with a flux density given by S_int (the int_flux_1p4_ghz parameter). If the angular_size_error value is null, then the component is unresolved with the quoted angular_size value representing an upper bound to the deconvolved angular size, and the component flux density is given by S_peak (the flux_1p4_ghz parameter).

Angular_Size_Error
The rms error in the estimated deconvolved angular size, Theta, in arcseconds. This is not given if the component is unresolved.

DB_Flux_1p4_GHz
The deboosted flux density of the 1.4-GHz component, in mJy. See Section 5.4 of the reference paper for more details on the deboosting procedures.

Contact Person

Questions regarding the ATLASD2CPT database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:24:46 EDT