J/MNRAS/457/4160 BETA pilot multi-epoch continuum survey (Heywood+, 2016)
Wide-field broad-band radio imaging with phased array feeds:
a pilot multi-epoch continuum survey with ASKAP-BETA.
Heywood I., Bannister K.W., Marvil J., Allison J.R., Ball L., Bell M.E.,
Bock D.-J., Brothers M., Bunton J.D., Chippendale A.P., Cooray F.,
Cornwell T.J., De Boer D., Edwards P., Gough R., Gupta N., Harvey-Smith L.,
Hay S., Hotan A.W., Indermuehle B., Jacka C., Jackson C.A., Johnston S.,
Kimball A.E., Koribalski B.S., Lenc E., Macleod A., McClure-Griffiths N.,
Mcconnell D., Mirtschin P., Murphy T., Neuhold S., Norris R.P., Pearce S.,
Popping A., Qiao R.Y., Reynolds J.E., Sadler E.M., Sault R.J.,
Schinckel A.E.T., Serra P., Shimwell T.W., Stevens J., Tuthill J.,
Tzioumis A., Voronkov M.A., Westmeier T., Whiting M.T.
<Mon. Not. R. Astron. Soc., 457, 4160-4178 (2016)>
=2016MNRAS.457.4160H 2016MNRAS.457.4160H (SIMBAD/NED BibCode)
ADC_Keywords: Interferometry ; Galaxies, radio ; Morphology
Keywords: instrumentation: interferometers - techniques: interferometric -
galaxies: general - radio continuum: galaxies
Abstract:
The Boolardy Engineering Test Array is a 6x12m dish interferometer
and the prototype of the Australian Square Kilometre Array Pathfinder
(ASKAP), equipped with the first generation of ASKAP's phased array
feed (PAF) receivers. These facilitate rapid wide-area imaging via the
deployment of simultaneous multiple beams within an ∼30deg2 field
of view. By cycling the array through 12 interleaved pointing
positions and using nine digitally formed beams, we effectively mimic
a traditional 1hx108 pointing survey, covering ∼150deg2 over
711-1015MHz in 12h of observing time. Three such observations were
executed over the course of a week. We verify the full bandwidth
continuum imaging performance and stability of the system via
self-consistency checks and comparisons to existing radio data. The
combined three epoch image has arcminute resolution and a 1σ
thermal noise level of 375µJy/beam, although the effective noise
is a factor of ∼3 higher due to residual sidelobe confusion. From
this we derive a catalogue of 3722 discrete radio components, using
the 35 per cent fractional bandwidth to measure in-band spectral
indices for 1037 of them. A search for transient events reveals one
significantly variable source within the survey area. The survey
covers approximately two-thirds of the Spitzer South Pole Telescope
Deep Field. This pilot project demonstrates the viability and
potential of using PAFs to rapidly and accurately survey the sky at
radio wavelengths.
Description:
The target field was observed with BETA on three separate occasions as
part of the commissioning and verification of the instrument. The
telescope delivers 304MHz of instantaneous bandwidth and for these
observations the sky frequency range was 711-1015MHz, corresponding to
a fractional bandwidth of 35 per cent. The data are captured with a
frequency resolution of 18.5kHz, using 16 416 frequency channels
across the band.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3.dat 150 3722 Source catalog
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 20 A20 --- Name Name (JHHMMSS.ss+DDMMSS.ss)
22- 29 F8.4 deg RAdeg Right ascension (J2000)
31- 38 F8.4 deg DEdeg Declination (J2000)
40- 46 F7.4 arcsec e_RAdeg Right Ascension error (1 σ)
48- 54 F7.4 arcsec e_DEdeg Declination error (1 σ)
56- 62 F7.2 mJy Sint Integrated flux density of the component
at 863MHz
64- 68 F5.2 mJy e_Sint Integrated flux density error
70- 76 F7.2 mJy/beam Speak Peak flux density of the component at
863MHz
78- 81 F4.2 mJy/beam e_Speak Peak flux density error
83- 86 F4.2 uJy/beam rms RMS local noise at the position of the
component
88- 92 F5.2 --- alpha ?=- Spectral index (S∝να)
94 A1 --- l_maj Limit flag on maj for unresolved
95-100 F6.2 arcsec maj Deconvolved major axis
102-106 F5.2 arcsec e_maj ? Deconvolved major axis error
108 A1 --- l_min Limit flag on min for unresolved
109-114 F6.2 arcsec min Deconvolved minor axis
116-120 F5.2 arcsec e_min ? Deconvolved minor axis error
122 A1 --- l_PA Limit flag on PA for unresolved
123-128 F6.2 deg PA Deconvolved position angle
130-135 F6.2 deg e_PA ? Deconvolved position angle error
137-140 I4 --- IDg Zero-indexed unique identifier for the
component (Gaussian component ID)
142-145 I4 --- IDs Zero-indexed unique identifier for the
source (Source ID)
147-150 I4 --- IDi Zero-indexed unique identifier for the
island (Island ID)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
(End) Patricia Vannier [CDS] 24-Nov-2016