Submm/mm galaxy counterpart identification using a characteristic density distribution

Stacey Alberts, Grant W. Wilson, Yu Lu, Seth Johnson, Min S. Yun, Kimberly S. Scott, Alexandra Pope, Itziar Aretxaga, Hajime Ezawa, David H. Hughes, Ryohei Kawabe, Sungeun Kim, Kotaro Kohno, Tai Oshima

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer Infrared Array Camera (IRAC) colours as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and Submillimeter Array-confirmed counterparts to AzTEC sources across three fields [Great Observatories Origins Deep Survey-North, -South and Cosmic Evolution Survey (COSMOS)], we develop a non-parametric IRACcolour-colour characteristic density distribution, which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around submillimetre galaxies (SMGs) and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beam size (~18 arcsec), this technique identifies ~85 per cent of SMG counterparts. For much larger beam sizes ("30 arcsec), we report identification rates of 33-49 per cent. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the Large Millimeter Telescope and Submillimeter Common User Bolometer Array 2 on the James Clerk Maxwell Telescope.

Original languageEnglish (US)
Pages (from-to)194-209
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume431
Issue number1
DOIs
StatePublished - Feb 22 2013
Externally publishedYes

Keywords

  • Galaxies: High-redshift
  • Infrared: Galaxies
  • Methods: Data analysis
  • Radio continuum: Galaxies
  • Submillimetre: Galaxies
  • Techniques: Photometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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