J/MNRAS/500/3821 Square Kilometre Array Science Data Challenge 1 (Bonaldi+ 2021)
Square Kilometre Array Science Data Challenge 1: analysis and results.
Bonaldi A., An T., Brueggen M., Burkutean S., Coelho B., Goodarzi H.,
Hartley P., Sandhu P.K., Wu C., Yu L., Zhoolideh Haghighi M.H., Anton S.,
Bagheri Z., Barbosa D., Barraca J.P., Bartashevich D., Bergano M.,
Bonato M., Brand J., de Gasperin F., Giannetti A., Dodson R., Jain P.,
Jaiswal S., Lao B., Liu B., Liuzzo E., Lu Y., Lukic V., Maia D.,
Marchili N., Massardi M., Mohan P., Morgado J.B., Panwar M., Prabhakar T.V.,
Ribeiro V.A.R.M., Rygl K.L.J., Sabz Ali V., Saremi E., Schisano E.,
Sheikhnezami S., Vafaei Sadr A., Wong A., Wong O.I.
<Mon. Not. R. Astron. Soc. 500, 3821-3837 (2021)>
=2021MNRAS.500.3821B 2021MNRAS.500.3821B (SIMBAD/NED BibCode)
ADC_Keywords: Radio sources ; Galaxies, radio ; Morphology
Keywords: methods: data analysis - techniques: image processing -
astronomical data bases: miscellaneous -
galaxies: statistics - radio continuum: galaxies
Abstract:
As the largest radio telescope in the world, the Square Kilometre
Array (SKA) will lead the next generation of radio astronomy. The
feats of engineering required to construct the telescope array will be
matched only by the techniques developed to exploit the rich
scientific value of the data. To drive forward the development of
efficient and accurate analysis methods, we are designing a series of
data challenges that will provide the scientific community with
high-quality datasets for testing and evaluating new techniques. In
this paper we present a description and results from the first such
Science Data Challenge (SDC1). Based on SKA MID continuum simulated
observations and covering three frequencies (560MHz, 1400MHz and
9200MHz) at three depths (8h, 100h and 1000h), SDC1 asked participants
to apply source detection, characterization and classification methods
to simulated data. The challenge opened in November 2018, with nine
teams submitting results by the deadline of April 2019. In this work
we analyse the results for 8 of those teams, showcasing the variety of
approaches that can be successfully used to find, characterise and
classify sources in a deep, crowded field. The results also
demonstrate the importance of building domain knowledge and expertise
on this kind of analysis to obtain the best performance. As
high-resolution observations begin revealing the true complexity of
the sky, one of the outstanding challenges emerging from this analysis
is the ability to deal with highly resolved and complex sources as
effectively as the unresolved source population.
Description:
The SDC1 dataset was released on the 25th of November
2019 and it is available on the SKA astronomers website
https://astronomers.skatelescope.org/ ska-science-data-challenge-1/.
It consists of 9 image files, in FITS format. Each file is a simulated
SKA continuum image in total intensity at 3 frequencies:
(i) 560MHz, representative of SKA Mid Band 1
(ii) 1.4GHz, representative of SKA Mid Band 2
(iii) 9.2GHz, representative of SKA Mid Band 5
Furthermore, 3 telescope integration depths per frequency are
provided:
(i) 8h, representative of a single-track observation
(ii) 100h, representative of a medium-depth integration
(iii) 1000h, representative of a deep integration
The SKA community was invited to retrieve the SDC1 images and
undertake source finding, source classification and characterization.
The results submitted should be catalogues of detected sources,
containing:
(i) Source coordinates (RA, Dec) to locate the centroids and where
appropriate the core positions
(ii) integrated primary-beam corrected flux density
(iii) core fraction (it is different from zero only for AGN)
(iv) major and minor axis size
(v) major axis position angle
(vi) Source population identification (one of AGN-steep, AGN-flat, SFG)
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tf560.dat 99 5251292 All sources of 560MHz image catalog
tt560.dat 99 274883 Training/validate dataset sources of
560MHz image catalog
tf1400.dat 99 1377375 All sources of image 1400MHz catalog
tt1400.dat 99 70737 Training/validate dataset sources of
1400MHz image catalog
tf9200.dat 99 76330 All sources of 9200MHz image catalog
tt9200.dat 99 1674 Training/validate dataset sources of
9200MHz image catalog
list.dat 110 3 List of fits images
fits/* . 3 Individual fits images
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See also:
https://astronomers.skatelescope.org/ska-science-data-challenge-1 :
SKA Home Page
Byte-by-byte Description of file: tf*.dat tt*.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- Id Identification number
10- 17 F8.5 deg RAdeg [] Core right ascension (J2000)
19- 27 F9.5 deg DEdeg Core declination (J2000)
29- 36 F8.5 deg RACdeg Centroid right ascension (J2000)
38- 46 F9.5 deg DECdeg Centroid declination (J2000)
48- 58 E11.5 Jy Flux Iintegrated primary-beam corrected flux density
60- 67 F8.5 --- CoreFrac Core fraction (different from zero only for AGN)
69- 77 F9.2 arcsec bmaj Major axis size
79- 87 F9.2 arcsec bmin Minor axis size
89- 95 F7.3 deg PA [] Major axis position angle
97 I1 --- Size [1/3] Size code (1)
99 I1 --- Class [1/3] Class code (2)
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Note (1): Size code defines the type of size used to define a source as follows:
1 = largest angular size
2 = gaussian
3 = exponential
Note (2): Class code as follows:
1 = steep-spectrum AGN
2 = flat-spectrum AGN
3 = star forming galaxy
--------------------------------------------------------------------------------
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 24 I5 --- Nx Number of pixels along X-axis
26- 30 I5 --- Ny Number of pixels along Y-axis
32- 52 A21 "datime" Obs.date Observatino date
54- 57 I4 MHz Freq Observed frequency
59- 65 I7 Kibyte size Size of FITS file
67- 84 A18 --- FileName Name of FITS file, in subdirectory fits
86-110 A25 --- Title Title of the FITS file
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Acknowledgements:
Alex Clarke, a.clarke(at)skatelescope.org
(End) Patricia Vannier [CDS] 28-Oct-2020