The Herschel Multi-Tiered Extragalactic Survey: source extraction and cross-identifications in confusion-dominated SPIRE images

Roseboom, I. G.; Oliver, S. J.; Kunz, M.; Altieri, B.; Amblard, A.; Arumugam, V.; Auld, R.; Aussel, H.; Babbedge, T.; Béthermin, M.; Blain, A.; Bock, J.; Boselli, A.; Brisbin, D.; Buat, V.; Burgarella, D.; Castro-Rodríguez, N.; Cava, A.; Chanial, P.; Chapin, E.; Clements, D. L.; Conley, A.; Conversi, L.; Cooray, A.; Dowell, C. D.; Dwek, E.; Dye, S.; Eales, S.; Elbaz, D.; Farrah, D.; Fox, M.; Franceschini, A.; Gear, W.; Glenn, J.; Solares, E. A. González; Griffin, M.; Halpern, M.; Harwit, M.; Hatziminaoglou, E.; Huang, J.; Ibar, E.; Isaak, K.; Ivison, R. J.; Lagache, G.; Levenson, L.; Lu, N.; Madden, S.; Maffei, B.; Mainetti, G.; Marchetti, L.; Marsden, G.; Mortier, A. M. J.; Nguyen, H. T.; O'Halloran, B.; Omont, A.; Page, M. J.; Panuzzo, P.; Papageorgiou, A.; Patel, H.; Pearson, C. P.; Pérez-Fournon, I.; Pohlen, M.; Rawlings, J. I.; Raymond, G.; Rigopoulou, D.; Rizzo, D.; Rowan-Robinson, M.; Portal, M. Sánchez; Schulz, B.; Scott, Douglas; Seymour, N.; Shupe, D. L.; Smith, A. J.; Stevens, J. A.; Symeonidis, M.; Trichas, M.; Tugwell, K. E.; Vaccari, M.; Valtchanov, I.; Vieira, J. D.; Vigroux, L.; Wang, L.; Ward, R.; Wright, G.; Xu, C. K.; Zemcov, M.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 409, Issue 1, pp. 48-65.

Advertised on:
11
2010
Number of authors
86
IAC number of authors
3
Citations
172
Refereed citations
160
Description
We present the cross-identification and source photometry techniques used to process Herschel SPIRE imaging taken as part of the Herschel Multi-Tiered Extragalactic Survey (HerMES). Cross-identifications are performed in map-space so as to minimize source-blending effects. We make use of a combination of linear inversion and model selection techniques to produce reliable cross-identification catalogues based on Spitzer MIPS 24-μm source positions. Testing on simulations and real Herschel observations shows that this approach gives robust results for even the faintest sources (S250 ~ 10 mJy). We apply our new technique to HerMES SPIRE observations taken as part of the science demonstration phase of Herschel. For our real SPIRE observations, we show that, for bright unconfused sources, our flux density estimates are in good agreement with those produced via more traditional point source detection methods (SUSSEXtractor) by Smith et al. When compared to the measured number density of sources in the SPIRE bands, we show that our method allows the recovery of a larger fraction of faint sources than these traditional methods. However, this completeness is heavily dependent on the relative depth of the existing 24-μm catalogues and SPIRE imaging. Using our deepest multiwavelength data set in the GOODS-N, we estimate that the use of shallow 24-μm catalogues in our other fields introduces an incompleteness at faint levels of between 20-40 per cent at 250μm.
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Formation and Evolution of Galaxies: Observations in Infrared and other Wavelengths
This IAC research group carries out several extragalactic projects in different spectral ranges, using space as well as ground-based telescopes, to study the cosmological evolution of galaxies and the origin of nuclear activity in active galaxies. The group is a member of the international consortium which built the SPIRE instrument for the
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