Name: Markos Trichas

Institution: Imperial College London

e-mail: m.trichas(no-spam)imperial.ac.uk

Partner Contry: UK

Science Meeting: Yes

User Meeting: None Selected

NGO Staff Meeting: None Selected

Presentation: Yes

Format: Poster

Title: Calibrating Photometric Redshift Techniques using GMOS Spectroscopy of Faint SWIRE-EN1 Galaxies

Co-author: Michael Rowan-Robinson (1), Duncan Farrah (2), Ian Waddington (3), Antonis Georgakakis (1) Thomas Babbedge (1)

Co-authors' Institutions: (1): Imperial College London, UK (2): Cornell University, USA (3): Sussex University, UK

Abstract:

We have carried out a systematic survey of faint SWIRE galaxies (21.5 &more; r &more;23.5), using GMOS, to test our photometric redshift techniques and SEDs template fitting methods. We used the red grating (R400) at a central wavelength of 7500 Angstroms. Nod-and-shuffle mode was used, which enabled us to remove sky contamination with high precision. Thirteen masks were observed giving 230 objects in total. Six of our pointings covered the ELAIS-N1 Deep X-ray Survey, one pointing targeted SWIRE EN-1 HST field and 6 pointings were randomly scattered across the SWIRE field. We have extracted a total of 198 secure redshifts in the redshift range 0.157 &more; z &more; 2.197. The median redshift of the whole sample is 0.7. The SEDs are modelled in terms of 6 galaxy templates and two AGN templates. Optical and IRAC 3.6 and 4.5 micron detections are used for the photometric redshift fitting procedure. The agreenment between spectroscopic and photometric redshifts is excellent with less than 5% rms scatter in (1 z) and about 4% outliers. Emission line diagnostics, where feasible, reveal that only 3% of the observed sources are AGN consistent with what our SED template fittings predict.