J/MNRAS/495/1706 SuperCLASS. I. (Harrison+, 2020)
SuperCLASS. I. The Super CLuster Assisted Shear Survey:
Project overview and data release 1.
Battye R.A., Brown M.L., Casey C.M., Harrison I., Jackson N.J., Smail I.,
Watson R.A., Hales C.A., Manning S.M., Hung C.-L., Riseley C.J.,
Abdalla F.B., Birkinshaw M., Demetroullas C., Chapman S., Beswick R.J.,
Muxlow T.W.B., Bonaldi A., Camera S., Hillier T., Kay S.T., Peters A.,
Sanders D.B., Thomas D.B., Thomson A.P., Tunbridge B., Whittaker L.,
(SuperCLASS Collaboration)
<Mon. Not. R. Astron. Soc. 495, 1706-1723 (2020)>
=2020MNRAS.495.1706B 2020MNRAS.495.1706B (SIMBAD/NED BibCode)
ADC_Keywords: Surveys; Radio sources; Photometry; Gravitational lensing;
Redshifts
Keywords: galaxies: evolution - large-scale structure of Universe -
cosmology: observations - radio continuum: galaxies -
Abstract:
The SuperCLuster Assisted Shear Survey (SuperCLASS) is a legacy
programme using the e-MERLIN interferometric array. The aim is to
observe the sky at L-band (1.4GHz) to a r.m.s. of 7uJy/beam over an
area of 1 square degrees centred on the Abell 981 supercluster. The
main scientific objectives of the project are: (i) to detect the
effects of weak lensing in the radio in preparation for similar
measurements that will be made by the Square Kilometre Array (SKA);
(ii) an extinction free census of star formation and AGN activity at z
up to 1. In this paper we give an overview of the project including
the science goals and multi-wavelength coverage before presenting the
first data release. We have analysed around 400 hours of e-MERLIN data
which has allowed us to create a DR1 mosaic covering an area
∼0.26 square degrees to the full depth. These observations have been
supplemented with complementary radio observations from the Karl G.
Jansky Very Large Array (VLA) and optical/near infra-red observations
taken with the Subaru, Canada-France-Hawaii and Spitzer Telescopes.
The main data product is a catalogue of 887 sources detected by the
VLA, of which 395 are detected by e-MERLIN and 197 of these are
resolved. We have investigated the size, flux and spectral index
properties of these sources and find them to be compatible with
previous studies. Preliminary photometric redshifts, and an assessment
of galaxy shapes measured in the radio data, combined with a
radio-optical cross-correlation technique to probe cosmic shear in a
supercluster environment, are presented in companion papers.
Description:
Three catalogues are provided containing L-band optical and BVr'i'z'
brightness and morphological data for sources in the SuperCLASS field,
consisting of ∼1 square degree in the Northern sky. Catalogues
superclassvladr1 and superclassemerlindr1 were created using data
from the VLA and e-MERLIN radio telescopes respectively on the 0.26
square degree DR1 region. VLA data is from 24 hours of observing over
112 pointings in A configuration in the 1-2GHz (L-band). The
correlator was configured to deliver 250kHz spectral channels (a total
of 4000) in full polarization with 1s time sampling. e-MERLIN data is
from 49 pointings over the Northern part of the same field, from
∼400-hours of data taken in the frequency range 1.204-1.717GHz, with
512 spectral channels of width 125kHz and 1s time integrations. Both
sets of radio data were imaged using forms of the CLEAN algorithm. The
VLA image Gaussian restoring beam had major axis 1.9arcsec, minor
axis 1.5arcsec and position angle 80deg east of north. The e-MERLIN
Gaussian restoring beam had major axis of 0.417arcsec, minor axis
0.232 arcsec and position angle 147.93deg east of north. Sources in
VLA images were detected and had their fluxes measured using the
PyBDSF software and all output columns from this are provided, along
with morphological classifications and measurements from the IM3SHAPE
and SuperCALS pipelines described in the accompanying papers. Sources
in e-MERLIN images were detected and had their fluxes measured using
the PyBDSF software, with catalogues being the union of detections
made with three smoothing scales applied to the image (0.4, 0.6,
2.0-arcsec). The catalogue superclasssubarufull is for the full
1.755 square degree SuperCLASS region. This contains AB magnitudes
measured from the Subaru Suprime-Cam observations of the SuperCLASS
field in BVr'i'z' bands. Sources were detected using the SExtractor
software, before having their redshifts inferred using the EAZY
software and their morphology measured with the IM3SHAPE software.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
subaru.dat 515 376380 Suprime-Cam data (table 4 of the paper)
vla.dat 791 887 VLA data (table 4 of the paper)
emerlin.dat 340 395 e-MERLIN data (table 4 of the paper)
list.dat 119 112 List of fits images
fits/* . 112 Individual fits images
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Byte-by-byte Description of file: subaru.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 12 F12.8 deg RAdeg Right Ascension (J2000)
14- 24 F11.8 deg DEdeg Declination (J2000)
26- 36 F11.8 mag Bmag ? Suprime-Cam B magnitude (AB)
38- 51 E14.8 mag e_Bmag ? Formal error on Bmag
53- 63 F11.8 mag Vmag ? Suprime-Cam V magnitude (AB)
65- 77 E13.8 mag e_Vmag ? Formal error on Vmag
79- 89 F11.8 mag rmag ? Suprime-Cam r' magnitude filter (AB)
91-102 E12.8 mag e_rmag ? Formal error on rmag
104-114 F11.8 mag imag ? Suprime-Cam i' magnitude filter (AB)
116-127 E12.8 mag e_imag ? Formal error on imag
129-139 F11.8 mag zmag ? Suprime-Cam z' magnitude filter (AB)
141-153 E13.8 mag e_zmag ? Formal error on zmag
155-165 F11.8 mag ymag ? Suprime-Cam y magnitude (AB)
167-177 F11.8 mag e_ymag ? Formal error on ymag
179-189 F11.8 mag [3.6] ? Spitzer 3.6um magnitude (AB)
191-203 F13.8 mag e_[3.6] []? Formal error on sp36
205-215 F11.8 mag [4.5] ? Spitzer 4.5um magnitude (AB)
217-229 F13.8 mag e_[4.5] []? Formal error on sp45
231-238 F8.1 --- Id Redshift source identifier
240-244 F5.3 --- za ? Redshift of best fitting all-template
SED (1)
246-255 E10.8 --- chiza ? Minimum chi-squared value of SED fit
at za (1)
257-261 F5.3 --- e_za ? Lower limit of 68 per cent confidence
interval on za (1)
263-267 F5.3 --- E_za ? Upper limit of 68 per cent confidence
interval on za (1)
269-273 F5.3 --- e_za95 ? Lower limit of 95 per cent confidence
interval on za (1)
275-279 F5.3 --- E_za95 ? Upper limit of 95 per cent confidence
interval on za (1)
281-283 F3.1 --- Nfilt ? Number of filters used in SED fit (1)
285-307 E23.20 --- e1 ? Fitted Sersic profile ellipticity
component e1 (2)
309-331 E23.20 --- e2 ? Fitted Sersic profile ellipticity
component e2 (2)
333-352 F20.17 pix Rad ? Fitted Sersic profile radius (2)
354-356 F3.1 --- RadRatio ? Ratio between radii of two components
fitted Sersic profile (2)
358-381 F24.17 --- BulgeA ? Amplitude of bulge component of fitted
Sersic profile (2)
383-406 F24.19 --- DiscA ? Amplitude of disc component of fitted
Sersic profile (2)
408-410 F3.1 --- BulgeIndex ? Sersic index of fitted bulge components (2)
412-414 F3.1 --- DiscIndex ? Sersic index of fitted disc component (2)
416-437 F22.18 --- BulgeFlux ? Flux of fitted bulge component (2)
439-461 F23.18 --- DiscFlux ? Flux of fitted disc component (2)
463-466 F4.1 --- FluxRatio ? Ratio of fitted component fluxes (2)
468-487 F20.15 --- snr ? Signal to Noise ratio in i' filter (2)
489-515 A27 --- SourceId ? SuperCLASS source identifier
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Note (1): Determined using the EAZY redshift estimation code of Brammer et al
(2008ApJ...686.1503B 2008ApJ...686.1503B).
Note (2): Determined from a fit of a two component Sersic model with disc (n=1)
and bulge (n=4) components, performed using the IM3SHAPE maximum likelihood
model fitting code of Zuntz et al (2013MNRAS.434.1604Z 2013MNRAS.434.1604Z).
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Byte-by-byte Description of file: vla.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- GausId Unique identifier for the PyBDSF
Gaussian (1)
6- 9 I4 --- IslId Unique identifier for the
PyBDSF Island (1)
11- 37 A27 --- SourceId Unique identifier for the
PyBDSF Source (1)
39 I1 --- WaveId [0] Wavelet scale (1)
41- 58 F18.14 deg RAdeg Right Ascension (J2000)
60- 81 E22.20 deg e_RAdeg Formal error on RAdeg
83- 99 F17.14 deg DEdeg Declination (J2000)
101-122 E22.20 deg e_DEdeg Formal error on DEdeg
124-145 E22.20 Jy FluxT Total integrated source flux from
PyBDSF (1)
147-168 E22.16 Jy e_FluxT Formal error on FluxT
170-191 E22.20 Jy/beam FluxP Peak flux density from PyBDSF (1)
193-214 E22.16 Jy/beam e_FluxP Formal error on FluxP
216-237 F22.20 deg Maj FWHM major axis of the best fit
Gaussian (1)
239-260 E22.20 deg e_Maj Formal error on Maj
262-283 F22.20 deg Min FWHM minor axis of the best fit
Gaussian (1)
285-306 E22.20 deg e_Min Formal error on Min
308-327 F20.16 deg PA Position angle of the best fit Gaussian,
measured east of north (1)
329-349 F21.17 deg e_PA Formal error on PA
351-372 E22.20 deg DCMaj Beam deconvolved FWHM major axis of the
best fit Gaussian (1)
374-395 E22.20 deg e_DCMaj Formal error on DCMaj
397-418 E22.20 deg DCMin Beam deconvolved FWHM minor axis of the
best fit Gaussian (1)
420-441 E22.20 deg e_DCMin Formal error on DCMin
443-462 F20.16 deg DCPA Beam deconvolved position angle of the
best fit Gaussian, measured east of
north (1)
464-484 F21.17 deg e_DCPA Formal error on DCPA
486-507 E22.20 Jy FluxTIsl Total integrated flux in the island in
which the source is located (1)
509-530 E22.20 Jy e_FluxTIsl Formal error on FluxTIsl
532-553 E22.16 Jy/beam Islrms Average background rms of island (1)
555-577 E23.16 Jy/beam Islmean Average background mean of island (1)
579-600 E22.16 Jy/beam ResIslrms Average residual background rms of
island (1)
602-624 E23.16 Jy/beam ResIslmean Average residual background mean of
island (1)
626 A1 --- SCode [CMS] Code defining source
structure (1)(7)
628 I1 --- ResFlag [0/1] Boolean flag defining whether source
is resolved (2)
630 I1 --- SMorphFlag [0/2] Flag defining morphological
classification of the source (3)
632-653 E22.20 --- e1unc ? Source e1 Ellipticity component of best
fit Sersic profile (4)
655-677 E23.19 --- e2unc ? Source e2 Ellipticity component of best
fit Sersic profile (4)
679-699 E21.19 --- e1cal ? Source e1 ellipticity component of best
fit Sersic profile, calibrated using the
SuperCALS pipeline (5)
701-722 E22.19 --- e2cal ? Source e2 ellipticity component of best
fit Sersic profile, calibrated using the
SuperCALS pipeline (5)
724 I1 --- Valid [0/1] Flag defining whether source has a
valid calibrated ellipticity from the
SuperCALS pipeline (5)
726-745 F20.16 pix RadIm3Shape ? Radius of the best fit Sersic
profile (4)
747-768 F22.19 --- e1calCorr ? Source e1 ellipticity component of best
fit Sersic profile calibrated using the
SuperCALS pipeline, with correction for
PSF ellipticity (6)
770-791 F22.19 --- e2calCorr ? Source e2 ellipticity component of best
fit Sersic profile calibrated using the
SuperCALS pipeline, with correction for
PSF ellipticity (6)
--------------------------------------------------------------------------------
Note (1): Measured using the PyBDSF source finder of Mohan and Rafferty
(2015ascl.soft02007M).
Note (2): Sources are classified as resolved where:
DCmaj>0 and DCmin>0 and Maj>thetamaj,
where theta_maj is the FWHM major axis size of the CLEAN restoring beam.
Note (3): Source morphology was classified by consensus of visual
classifications by a number of the authors. Complex morphology is sources
which are extended with multiple components, whilst simple morphology is
sources which are well fit by a single component (such as star-forming
galaxies).
Flag defining morphological classification of the source as follows:
0 = Unresolved
1 = Complex morphology
2 = Simple morphology
Note (4): Determined from a fit of a Sersic model, performed using the IM3SHAPE
maximum likelihood model fitting code of Zuntz et al (2013MNRAS.434.1604Z 2013MNRAS.434.1604Z).
Note (5): Ellipticity calibrated using the SuperCALS method: simulated sources
of known shape are injected into the CLEAN residual image at the location of
each real source. These simulated sources then have their shapes measured, to
determine the bias on e1 and e2 from the residual noise in the image. This
bias is calculated as a full function of e1 and e2 and then used to correct
the uncalibrated_supercals columns.
Note (6): These columns also contain a correction to the source ellipticity
components from the known position angle of the CLEAN restoring beam.
Note (7): Code defining source structure as follows:
S = single Gaussian alone in island
C = single Gaussian in island with others
M = multi Gaussian
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Byte-by-byte Description of file: emerlin.dat
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Bytes Format Units Label Explanations
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1- 27 A27 --- SourceId Unique identifier for the PyBDSF Source (1)
29- 30 I2 --- IslId [0/18] Unique identifier for the
PyBDSF Island (1)
32- 42 F11.7 deg RAdeg Right Ascension (J2000)
44- 51 E8.2 deg e_RAdeg Formal error on RAdeg
53- 63 F11.8 deg DEdeg Declination (J2000)
65- 72 E8.2 deg e_DEdeg Formal error on DEdeg
74- 84 E11.9 Jy FluxT Total integrated source flux
from PyBDSF (1)
86- 93 E8.2 Jy e_FluxT Formal error on FluxT
95-105 E11.9 Jy/beam FluxP Peak flux density from PyBDSF (1)
107-114 E8.2 Jy/beam e_FluxP Formal error on FluxP
116-126 E11.9 deg Maj FWHM major axis of the best fit
Gaussian (1)
128-138 E11.9 deg e_Maj Formal error on Maj
140-150 E11.9 deg Min FWHM minor axis of the best fit
Gaussian (1)
152-162 E11.9 deg e_Min Formal error on Min
164-176 F13.9 deg PA Position angle of the best fit Gaussian,
measured east of north (1)
178-190 F13.9 deg e_PA Formal error on PA
192-202 E11.9 deg DCMaj Beam deconvolved FWHM major axis of the
best fit Gaussian (1)
204-214 E11.9 deg e_DCMaj Formal error on DCMaj
216-226 E11.9 deg DCMin Beam deconvolved FWHM minor axis of the
best fit Gaussian (1)
228-238 E11.9 deg e_DCMin Formal error on DCMin
240-252 F13.9 deg DCPA Beam deconvolved position angle of the best
fit Gaussian, measured east of north (1)
254-266 F13.9 deg e_DCPA Formal error on DCPA
268-278 E11.9 Jy FluxTIsl Total integrated flux in the island in
which the source is located (1)
280-290 E11.9 Jy e_FluxTIsl Formal error on FluxTIsl
292-299 E8.2 Jy/beam Islrms Average background rms of island (1)
301-309 E9.2 Jy/beam Islmean Average background mean of island (1)
311-318 E8.2 Jy/beam ResIslrms Average residual background rms of
island (1)
320-330 E11.9 Jy/beam ResIslmean Average residual background mean of
island (1)
332 A1 --- SCode [CMS] Code defining source structure (1)(5)
334-336 F3.1 arcsec ScaleFlag Smoothing scale in e-MERLIN image in which
source was detected (2)
338 I1 --- ResFlag [0/1] Flag defining whether source is
resolved (3)
340 I1 --- SMorphFlag [0/2] Flag defining morphological
classification of the source (4)
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Note (1): Measured using the PyBDSF source finder of Mohan and Rafferty
(2015ascl.soft02007M).
Note (2): In order to account for resolving-out of diffuse sources in the
interferometer image, the PyBDSF source finder was run on three different
e-MERLIN images, smoothed to 0.4, 0.6, 2.0 arcsec. This catalogue is formed
from the union of the three catalogues at different smoothing scales.
Note (3): Sources are classified as resolved where:
DCmaj>0 and DCmin>0 and Maj>thetamaj,
where theta_maj is the FWHM major axis size of the CLEAN restoring beam.
Note (4): Source morphology was classified by consensus of visual
classifications by a number of the authors. Complex morphology is sources
which are extended with multiple components, whilst simple morphology is
sources which are well fit by a single component (such as star-forming
galaxies).
Flag defining morphological classification of the source as follows:
0 = Unresolved
1 = Complex morphology
2 = Simple morphology
Note (5): Code defining source structure as follows:
S = single Gaussian alone in island
C = single Gaussian in island with others
M = multi Gaussian
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 22 I3 --- Nx Number of pixels along X-axis
24- 26 I3 --- Ny Number of pixels along Y-axis
28- 48 A21 "datime" Obs.date Observation date
50- 52 I3 Kibyte size Size of FITS file
54- 85 A32 --- FileName Name of FITS file, in subdirectory fits
87-119 A33 --- Title Title of the FITS file
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Acknowledgements:
Ian Harrison, ian.harrison-2(at)manchester.ac.uk
(End) Patricia Vannier [CDS] 05-Feb-2020