CSIRO Publishing blank image blank image blank image blank imageBooksblank image blank image blank image blank imageJournalsblank image blank image blank image blank imageAbout Usblank image blank image blank image blank imageShopping Cartblank image blank image blank image You are here: Journals > PASA   
PASA
http://asa.astronomy.org.au/
  Publications of the Astronomical Society of Australia
 
blank image Search
 
blank image blank image
blank image
 
  Advanced Search
   

Journal Home
Content
Current Issue
All Issues
Special Issues
Research Fronts

 

Open Access Article << Previous     |     Next >>   Contents Vol 29(3)

The Completeness and Reliability of Threshold and False-discovery Rate Source Extraction Algorithms for Compact Continuum Sources

M. T. Huynh A G , A. Hopkins B F , R. Norris C , P. Hancock D F , T. Murphy D E F , R. Jurek C and M. Whiting C

A International Centre for Radio Astronomy Research, M468, University of Western Australia, Crawley, WA 6009, Australia
B Australian Astronomical Observatory, P.O. Box 296, Epping NSW 1710, Australia
C CSIRO Astronomy & Space Sciences, Australia Telescope National Facility, PO Box 76, Epping NSW 1710, Australia
D Sydney Institute for Astronomy, School of Physics, The University of Sydney, NSW 2006, Australia
E School of Information Technologies, The University of Sydney, NSW 2006, Australia
F ARC Centre of Excellence for All-sky Astrophysics (CAASTRO)
G Corresponding author. Email: minh.huynh@uwa.edu.au

Publications of the Astronomical Society of Australia 29(3) 229-243 http://dx.doi.org/10.1071/AS11026
Submitted: 12 June 2011  Accepted: 19 October 2011   Published: 14 December 2011


 
 Full Text
 PDF (1.4 MB)
 Export Citation
 Print
  
Abstract

The process of determining the number and characteristics of sources in astronomical images is so fundamental to a large range of astronomical problems that it is perhaps surprising that no standard procedure has ever been defined that has well-understood properties with a high degree of statistical rigour on completeness and reliability. The Evolutionary Map of the Universe (EMU) survey with the Australian Square Kilometre Array Pathfinder (ASKAP), a continuum survey of the Southern Hemisphere up to declination +30°, aims to utilise an automated source identification and measurement approach that is demonstrably optimal, to maximise the reliability, utility and robustness of the resulting radio source catalogues. A key stage in source extraction methods is the background estimation (background level and noise level) and the choice of a threshold high enough to reject false sources, yet not so high that the catalogues are significantly incomplete. In this analysis, we present results from testing the SExtractor, Selavy (Duchamp), and sfind source extraction tools on simulated data. In particular, the effects of background estimation, threshold and false-discovery rate settings are explored. For parameters that give similar completeness, we find the false-discovery rate method employed by sfind results in a more reliable catalogue compared to the peak threshold methods of SExtractor and Selavy.

Keywords: methods: data analysis — radio continuum: general — techniques: image processing


References

Bertin, E. and Arnouts, S., 1996, A&AS, 117, 393

Da Costa, G. S., 1992, in Astronomical CCD Observing and Reduction Techniques, ed. S. B. Howell, ASP, 23, 90

DeBoer, D. R., 2009, IEEE Proceedings, 97, 1507
CrossRef |

Hopkins, A. M., Mobasher, B., Cram, L. and Rowan-Robinson, M., 1998, MNRAS, 296, 839
CrossRef |

Hopkins, A. M., Miller, C. J., Connolly, A. J., Genovese, C., Nichol, R. C. and Wasserman, L., 2002, AJ, 123, 1086

Huynh, M. T., Jackson, C. A., Norris, R. P. and Prandoni, I., 2005, AJ, 130, 1373

Johnston, S. et al., 2008, ExA, 22, 151
CrossRef |

Mauch, T., Murphy, T., Buttery, H. J., Curran, J., Hunstead, R. W., Piestrzynski, B., Robertson, J. G. and Sadler, E. M., 2003, MNRAS, 342, 1117
CrossRef |

Miller, C. J. et al., 2001, AJ, 122, 3492

Murphy, T., Mauch, T., Green, A., Hunstead, R. W., Piestrzynska, B., Kels, A. P. and Sztajer, P., 2007, MNRAS, 382, 382
CrossRef |

Norris, R. P., et al., 2011, submitted to PASA

Planck Collaboration, 2011, submitted to A&A, arXiv:1101.2041

Rich, J. W., de Blok, W. J. G., Cornwell, T. J., Brinks, E., Walter, F., Bagetakos, I. and Kennicutt, R. C., 2008, AJ, 136, 2897
| CAS |

Schinnerer, E. et al., 2007, ApJS, 172, 46
CrossRef | CAS |

Schinnerer, E. et al., 2010, ApJS, 188, 384
CrossRef |

White, R. L., Becker, R. H., Helfand, D. J. and Gregg, M. D., 1997, ApJ, 475, 479
CrossRef |

Whiting, M. T., 2008, in Galaxies in the Local Volume, ed. B. S. Koribalski & H. Jerjen, Astrophysics and Space Science Reviews (Springer), 343.

Wilman, R. J., 2008, MNRAS, 388, 1335

Wilman, R. J., Jarvis, M. J., Mauch, T., Rawlings, S. and Hickey, S., 2010, MNRAS, 405, 447


   
 
    
Legal & Privacy | Contact Us | Help

CSIRO

© CSIRO 1996-2013