J/MNRAS/441/2555 ATLAS 1.4GHz Data Release 2 (Hales+, 2014)
ATLAS 1.4GHz 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. R. Astron. Soc., 441, 2555-2592 (2014)>
=2014MNRAS.441.2555H 2014MNRAS.441.2555H
ADC_Keywords: Surveys ; Galaxy catalogs ; Radio sources
Keywords: polarization - methods: data analysis - techniques: polarimetric -
surveys - radio continuum: galaxies
Abstract:
This is the first of two papers describing the second data release
(DR2) of the Australia Telescope Large Area Survey at 1.4GHz, which
comprises deep wide-field observations in total intensity, linear
polarization, and circular polarization over the Chandra Deep
Field-South and European Large Area Infrared Space Observatory
Survey-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 multipointing images are
30µJy/beam at approximately 12"x6" resolution over a
combined area of 6.4deg2. In this paper we present detailed
descriptions of our 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.
We present the DR2 images and catalogues of components (discrete
regions of radio emission) and sources (groups of physically
associated radio components). We describe new analytic methods to
account for resolution bias and Eddington bias when constructing
differential number counts of radio components.
Description:
ATLAS observations of the CDF-S and ELAIS-S1 fields were obtained with
the ATCA, a synthesis telescope consisting of six 22m alt-az antennas
on an east-west baseline. Each antenna is equipped with linearly
polarized feeds used to measure all four polarization products (XX,
YY, XY, YX), from which all four Stokes parameters (I, Q, U, V) can be
derived. Noise diodes in the feed horns of each antenna replace the
need to observe a polarization position angle calibrator to derive
absolute XY phase.
We supplemented our 1.4GHz radio observations with data at infrared
and optical wavelengths.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 144 2588 ATLAS 1.4GHz DR2 component catalogue
tableb1.dat 355 2221 ATLAS 1.4GHz DR2 source catalogue
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See also:
II/253 : Chandra Deep Field South: multi-colour data (Wolf+, 2008)
J/A+A/451/881 : ESIS BVR catalog, ELAIS-S1 (Berta+, 2006)
Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- ID Component identification number (1)
10- 16 A7 --- --- [ATLAS2_]
17- 36 A20 --- ATLAS2 Full component name (JHHMMSS.ss+DDMMSS.sA) (2)
38- 46 F9.6 deg RAdeg Right ascension (J2000)
48- 57 F10.6 deg DEdeg Declination (J2000)
59- 62 F4.2 arcsec e_RAdeg Error in right ascension
64- 67 F4.2 arcsec e_DEdeg Error in declination
69- 75 F7.2 --- SNR [5/9500] Signal to noise ratio of raw detection
77- 81 F5.3 mJy rms [0.01/0.1] Local rms noise value (in mJy/beam)
83- 86 F4.2 --- bws [0.8/1] Local bandwidth smearing value
88- 94 F7.3 mJy Speak [0.1/964] Peak 1.4GHz surface brightness
corrected for bandwidth smearing (in mJy/beam)
96-101 F6.3 mJy e_Speak [0.01/50] Error in peak surface brightness
(in mJy/beam)
103-110 F8.3 mJy Sint [0.08/1068] Integrated surface brightness
112-117 F6.3 mJy e_Sint Error in integrated surface brightness
119-123 F5.3 --- Varea [0/1] Visibility area
125 A1 --- l_theta Limit flag on theta (upper bound)
126-130 F5.2 arcsec theta [0/50] Deconvolved angular size or upper bound
132-135 F4.2 arcsec e_theta ?=- Error in deconvolved angular size
137-144 F8.3 mJy SML [0.1/1068] Deboosted flux density
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Note (1): This gives the internal designation of the source used within our
data processing. The form, FDbbbbCj, is a composite of three descriptors
plus an optional fourth:
* The first (F) is a single character that represents the ATLAS field:
"C" for CDF-S, or "E" for ELAIS-S1.
* The second descriptor (D) is a single character that represents the nature
of detection: "T" for total intensity, or "L" for linear polarization.
* The third descriptor (bbbb) is an integer (1 to 4 digits) that gives the
blob identification number assigned by bolbcat.
* The fourth descriptor (Cj) is only suffixed for those components that were
obtained through refitting all or part of the original blob, using either
IMFIT (denoted by Cj), or bolbca (denoted by Fj), for the jth extracted
component from a given blob.
Note (2): The form is ATLAS2_JHHMMSS.ss+DDMMSS.sT 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 declination, DDMMSS.s are the degrees, minutes and truncated seconds
of declination, and the single final character specifier indicates the nature
of detection as T (total) or L (Linear polarization).
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Byte-by-byte Description of file: tableb1.dat
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Bytes Format Units Label Explanations
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1- 5 A5 --- ID Source identification number (1)
7- 13 A7 --- --- [ATLAS2_]
14- 33 A20 --- ATLAS2 Full component name (JHHMMSS.ss+DDMMSS.s)
34- 41 A8 --- I1 ?=0 ID of total intensity component 1 (2)
43- 50 A8 --- I2 ?=0 ID of total intensity component 2 (2)
52- 59 A8 --- I3 ?=0 ID of total intensity component 3 (2)
61- 68 A8 --- I4 ?=0 ID of total intensity component 4 (2)
70- 77 A8 --- I5 ?=0 ID of total intensity component 5 (2)
79- 86 A8 --- I6 ?=0 ID of total intensity component 6 (2)
88- 95 A8 --- L1 ?=0 ID of inear polarisation component 1 (2)
97-104 A8 --- L2 ?=0 ID of inear polarisation component 2 (2)
106-113 A8 --- L3 ?=0 ID of inear polarisation component 3 (2)
115-123 I9 --- Gr.A ?=999999999 Group A classifications (3)
125-133 I9 --- Gr.B ?=999999999 Group B classifications (3)
135-143 I9 --- Gr.C ?=999999999 Group C classifications (3)
145-152 F8.3 mJy AI ?=0 Group A total intensity flux density
154-159 F6.3 mJy e_AI ?=0 Group A error in total intensity flux density
161-166 F6.3 mJy AL ?=0 Group A linearly polarised flux density
168-172 F5.3 mJy e_AL ?=0 Group A error in linearly polarised
flux density
174-181 F8.3 mJy BI ?=0 Group B total intensity flux density
183-188 F6.3 mJy e_BI ?=0 Group B error in total intensity flux density
190-195 F6.3 mJy BL ?=0 Group B linearly polarised flux density
197-201 F5.3 mJy e_BL ?=0 Group B error in linearly polarised
flux density
203-209 F7.3 mJy CI ?=0 Group C total intensity flux density
211-216 F6.3 mJy e_CI ?=0 Group C error in total intensity flux density
218-223 F6.3 mJy CL ?=0 Group C linearly polarised flux density
225-229 F5.3 mJy e_CL ?=0 Group C error in linearly polarised
flux density
231-237 A7 --- --- [SWIRE3_]
238-256 A19 --- SWIRE3 SWIRE-DR3 cross-matched source
(JHHMMSS.ss+DDMMSS.s)
258-266 F9.6 deg RAdeg Right ascension (J2000)
268-277 F10.6 deg DEdeg Declination (J2000)
279-286 F8.3 mJy I [0.1/1355] Total intensity 1.4GHz flux density
of source
288-293 F6.3 mJy e_I Error in total intensity flux density of source
295 A1 --- l_L Limit flag on L (upper bound)
296-301 F6.3 mJy L [0.1/59] Linearly polarised flux density of
source or upper bound
303-307 F5.3 mJy e_L ?=- Error in linearly polarised flux density
of source
309-316 F8.2 uJy S3.6 ?=0 SWIRE 3.6µm flux density
318-325 F8.2 uJy S4.5 ?=0 SWIRE 4.5µm flux density
327-334 F8.2 uJy S5.8 ?=0 SWIRE 5.8µm flux density
336-343 F8.2 uJy S8.0 ?=0 SWIRE 8.0µm flux density
345-353 F9.2 uJy S24 ?=0 SWIRE 24.0µm flux density
355 I1 --- Cl [0/9] Source classification: 0=AGN,
1=SFG (Star-Forming Galaxy), 2=star, 9=unknown
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Note (1): This gives the internal designation of the source used within our
data processing. The form Fnnnn is a composite of two descriptors:
* The first (F) is a single character that represents the ATLAS field:
"C" for CDF-S or "E" for ELAIS-S1.
* The second descriptor (nnnn) is an integer (1 to 4 digits) that reflects
the ordering of sources within each field.
Note (2): Component identification number, ID, of tablea1.dat.
Note (3): Component groupings and their type classifications according to the
linear polarization-total intensity association scheme presented in Sect. 6.2.
Up to 3 groups may be provided, labelled A, B, and C. Each group is specified
by a 9-digit string, where from left to right each digit corresponds to the
respective components given in columns I1-L3. If a component is not included in
a particular group, then its respective digit is set to 9. All components
belonging to a given group have their respective digit set to the type
classification for that group. Group A always represents the collection of all
components comprising the source. Groups B and C represent subsets of
components.
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History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 09-Feb-2015